bluuebunny/crossref_metadata_2025 huggingface dataset:
Public pension privatization
Authors: Dixon John , Hyde Mark
Published: May 2003

Although neo‐classical economics has undoubtedly driven the global pension privatization reform agenda, it does not provide an adequate framework for the reform of retirement income protection. Indeed, it poses salient decision risks for policy‐makers because of its naturalist epistemology and agency ontology, which deny both the value of hermeneutic knowledge and the existence of structural imperatives. When confronted with the challenge of income maintenance for those in retirement, policy‐makers must necessarily tackle strategically important, values‐laden questions. This requires them to engage in policy discourses that are informed by competing welfare ideologies. Reflecting these discourses, national governments have adopted three reform approaches to public pension privatization. All are consistent with values of community solidarity, social cohesion and citizenship rights, which are seen by national governments to be preferable to the values that underpin neo‐classical economic analysis, namely, individual responsibility, freedom of choice and contractual rights.
The economic impact of landmines on developing countries
Authors: Bier Gregory L.
Published: May 2003

Leaders of the world economy take the infrastructure dimension of the environment for granted. As these leaders attempt to develop trade with third‐world countries they are naÏve about constraints placed on development by past civil strife. When the international community helps to reconstruct and develop trade with these countries it must acknowledge the damage often caused during the conflict. Often this means dealing with the removal of landmines. Economic leaders often relate rebuilding the infrastructure and ridding the country of landmines to the military even while militaries are ill equipped for this. Concludes that an understanding of the intricate nature of infrastructure issues in the transition from conflict and strife to peace must be built.
Self‐referral to specialists – a dodgy proposition
Authors: Makkar Ravinder P.S. , Monga Amitabh , Arora Anju , Mukhopadhyay Surabhi , Gupta Ajay Kr.
Published: May 2003

Patients are often ill‐equipped to know which speciality to choose for their health problem. Especially in the presence of non‐specific symptoms, choosing the right specialist might not be so obvious. In such cases, misdirected self‐referrals by patients to self‐chosen specialists can sometimes lead to misdiagnosis resulting in unwarranted delays in getting the right treatment. The general physicians, on the other hand, are in a unique position to oversee the big picture of patients’ health, and are therefore better equipped to identify and sort out their individual health problems. Hence instead of a specialist if the first place of contact for patients is a general physician, they are likely to be guided along the right path of treatment for their various health problems. Such a system will minimize errors on the part of the patients by making certain that they are referred to the appropriate specialists.
Success factors for implementation of the balanced scorecard in a NHS multi‐agency setting
Authors: Radnor Zoe , Lovell Bill
Published: May 2003

Even though the balanced scorecard (BSC) has become a highly popular performance management tool, usage in local public sector National Health Service (NHS) organisations is still rare. This paper conditionally outlines some grounds in supporting such usage. In particular underlying conceptual concerns with the BSC system and its implementation pitfalls require full consideration. This paper then outlines some factors to be taken into account for “successful” BSC implementation in a NHS multi‐agency setting. These findings emerged from a series of focus groups that took place with contributors drawn from all the key organisations within the Bradford Health Action Zone. Finally, this paper argues that if key criteria are met, successful implementation of the BSC may then proceed. However, “blind” BSC implementation without consideration of these factors may result in potential “failure”.
3D collar design creation
Authors: Fang Jing‐Jing
Published: May 2003

This preliminary research revolute the conventional clothing design process by true designs from three‐dimensional (3D) rather than two‐dimensional. The aim of the research is to develop a handy 3D clothing design software tool for general garment designers. Work carried out in this paper is the preliminary result of the 3D software infrastructure. In addition, 3D collar design based on a mathematical formula is accomplished as a template for other garment portions. Object‐oriented technology is invoked as a tool for software developing. The system is divided into two major modulus, the user interface and the kernel. The user interface is used to collect messages from the users, and then send it to the kernel for further computations. Moreover, it exhibits real‐time pictures received from the kernel. The major work of the kernel is to handle the operations that are called by the user interface. In this paper two basal collars, convertible collar and shirt collar, are illustrated as diversified figurations.
Forecasting women's apparel sales using mathematical modeling
Authors: Frank Celia , Garg Ashish , Sztandera Les , Raheja Amar
Published: May 2003

Traditionally, statistical time series methods like moving average (MA), auto‐regression (AR), or combinations of them are used for forecasting sales. Since these models predict future sales only on the basis of previous sales, they fail in an environment where the sales are more influenced by exogenous variables such as size, price, color, climatic data, effect of media, price changes or campaigns. Although, a linear regression model can take these variables into account its approximation function is restricted to be linear. Soft computing methods such as fuzzy logic, artificial neural networks (ANNs), and genetic algorithms offer an alternative taking into account both endogenous and exogenous variables and allowing arbitrary non‐linear approximation functions derived (learned) directly from the data. In this paper, two approaches have been investigated for forecasting women's apparel sales, statistical time series modeling, and modeling using ANNs. Four years' sales data (1997‐2000) were used as backcast data in the model and a forecast was made for 2 months of the year 2000. The performance of the models was tested by comparing one of the goodness‐of‐fit statistics, R2, and also by comparing actual sales with the forecasted sales of different types of garments. On an average, an R2 of 0.75 and 0.90 was found for single seasonal exponential smoothing and Winters' three parameter model, respectively. The model based on ANN gave a higher R2 averaging 0.92. Although, R2 for ANN model was higher than that of statistical models, correlations between actual and forecasted were lower than those found with Winters' three parameter model.
Factors during tumble drying that influence dimensional stability and distortion of cotton knitted fabrics
Authors: Higgins L. , Anand S.C. , Hall M.E. , Holmes D.A.
Published: May 2003

The length and width shrinkages, skewness, spirality and moisture content of three weft knitted cotton structures, plain single jersey, interlock and lacoste, were determined at regular intervals during tumble drying. Significant length and width shrinkages occurred in all three structures with the amount of shrinkage increasing rapidly in plain single jersey and lacoste as their moisture contents fell below 30 per cent. Distortion was less affected by tumble drying. An attempt was made to isolate the effects of heat and agitation during tumble drying. It has been demonstrated that similar patterns of shrinkage and distortion occur whether heat is applied during tumble drying or not. The tumbling action in a tumble drier has the greatest influence on the dimensional stability and distortion of weft knitted cotton fabrics.
The relationship between technology and logistics third‐party providers
Authors: Sauvage Thierry
Published: May 2003

Our work discusses the results of a survey among French logistics service providers. In a highly competitive context characterized by “time compression”, technological effort becomes a key variable and a means of differentiation between third‐party logistics providers. The success of logistics outsourcing relationships is entrenched in the third‐party's technological ability to improve the supply chain reactivity.
Value‐adding partnerships and co‐opetition models in the grocery industry
Authors: Kotzab Herbert , Teller Christoph
Published: May 2003

Leading representatives of the European grocery industry formed the European efficient consumer response initiative in 1995. The goal of this strategic alliance is set to reengineer the way in which business is done in the industry by implementing cooperative strategies between retailer and manufacturer in order to fulfill consumer wishes better, faster and at less cost. Efficient consumer response appears thereby in many facets, from a “simple” dyadic value‐adding partnership to a sophisticated form of co‐opetition, where supply chain members have both relationship types – competition and cooperation – at the same time. Our paper discusses these issues first on theoretical bases and then presents empirical results of a comprehensive analysis within a selected European efficient consumer response initiative showing the success factors of managing efficient consumer response partnership relations.
Effects of Market Reform on the Trading Costs and Depths of Nasdaq Stocks
Authors: Barclay Michael J. , Christie William G. , Harris Jeffrey H. , Kandel Eugene , Schultz Paul H.
Published: May 2003

The relative merits of dealer versus auction markets have been a subject of significant and sometimes contentious debate. On January 20, 1997, the Securities and Exchange Commission began implementing reforms that would permit the public to compete directly with Nasdaq dealers by submitting binding limit orders. Additionally, superior quotes placed by Nasdaq dealers in private trading venues began to be displayed in the Nasdaq market. We measure the impact of these new rules on various measures of performance, including trading costs and depths. Our results indicate that quoted and effective spreads fell dramatically without adversely affecting market quality.
Payments for Order Flow on Nasdaq
Authors: Kandel Eugene , Marx Leslie M.
Published: May 2003

We present a model of Nasdaq that includes the two ways in which marketmakers compete for order flow: quotes and direct payments. Brokers in our model can execute small trades through a computerized system, preferencing arrangements with marketmakers, or vertical integration into market making. The comparative statics in our model differ from those of the traditional model of dealer markets, which does not capture important institutional features of Nasdaq. We also show that the empirical evidence is inconsistent with the traditional model, which suggests that preferencing and vertical integration are important components in understanding Nasdaq.
Costs of Equity Capital and Model Mispricing
Authors: Pástor Ľuboš , Stambaugh Robert F.
Published: May 2003

Costs of equity for individual firms are estimated in a Bayesian framework using several factor‐based pricing models. Substantial prior uncertainty about mispricing often produces an estimated cost of equity close to that obtained with mispricing precluded, even for a stock whose average return departs significantly from the pricing model's prediction. Uncertainty about which pricing model to use is less important, on average, than within‐model parameter uncertainty. In the absence of mispricing uncertainty, uncertainty about factor premiums is generally the largest source of overall uncertainty about a firm's cost of equity, although uncertainty about betas is nearly as important.
Incomplete Markets and Security Prices: Do Asset‐Pricing Puzzles Result from Aggregation Problems?
Authors: Jacobs Kris
Published: May 2003

This paper investigates Euler equations involving security prices and household‐level consumption data. It provides a useful complement to many existing studies of consumption‐based asset pricing models that use a representative‐agent framework, because the Euler equations under investigation hold even if markets are incomplete. It also provides a useful complement to simulation‐based studies of market incompleteness. The empirical evidence indicates that the theory is rejected by the data along several dimensions. The results therefore indicate that some well‐documented asset‐pricing puzzles do not result from aggregation problems for the preferences under investigation.
Improved Methods for Tests of Long‐Run Abnormal Stock Returns
Authors: Lyon John D. , Barber Brad M. , Tsai Chih‐Ling
Published: May 2003

We analyze tests for long‐run abnormal returns and document that two approaches yield well‐specified test statistics in random samples. The first uses a traditional event study framework and buy‐and‐hold abnormal returns calculated using carefully constructed reference portfolios. Inference is based on either a skewness‐adjustedt‐statistic or the empirically generated distribution of long‐run abnormal returns. The second approach is based on calculation of mean monthly abnormal returns using calendar‐time portfolios and a time‐seriest‐statistic. Though both approaches perform well in random samples, misspecification in nonrandom samples is pervasive. Thus, analysis of long‐run abnormal returns is treacherous.
Two‐Pass Tests of Asset Pricing Models with Useless Factors
Authors: Kan Raymond , Zhang Chu
Published: May 2003

In this paper we investigate the properties of the standard two‐pass methodology of testing beta pricing models with misspecified factors. In a setting where a factor is useless, defined as being independent of all the asset returns, we provide theoretical results and simulation evidence that the second‐pass cross‐sectional regression tends to find the beta risk of the useless factor priced more often than it should. More surprisingly, this misspecification bias exacerbates when the number of time series observations increases. Possible ways of detecting useless factors are also examined.
Herding among Investment Newsletters: Theory and Evidence
Authors: Graham John R.
Published: May 2003

A model is developed which implies that if an analyst has high reputation or low ability, or if there is strong public information that is inconsistent with the analyst's private information, she is likely to herd. Herding is also common when informative private signals are positively correlated across analysts. The model is tested using data from analysts who publish investment newsletters. Consistent with the model's implications, the empirical results indicate that a newsletter analyst is likely to herd on Value Line's recommendation if her reputation is high, if her ability is low, or if signal correlation is high.
An Empirical Comparison of Forward‐Rate and Spot‐Rate Models for Valuing Interest‐Rate Options
Authors: Bühler Wolfgang , Uhrig‐Homburg Marliese , Walter Ulrich , Weber Thomas
Published: May 2003

Our main goal is to investigate the question of which interest‐rate options valuation models are better suited to support the management of interest‐rate risk. We use the German market to test seven spot‐rate and forward‐rate models with one and two factors for interest‐rate warrants for the period from 1990 to 1993. We identify a one‐factor forward‐rate model and two spot‐rate models with two factors that are not significantly outperformed by any of the other four models. Further rankings are possible if additional criteria are applied.
Are Tax Effects Important in the Long‐Run Fisher Relationship? Evidence from the Municipal Bond Market
Authors: Crowder William J. , Wohar Mark E.
Published: May 2003

Are nominal bonds appropriately discounted for taxes? Empirical estimates of the response of nominal interest rates to changes in inflation, the Fisher effect, have failed to produce a definitive answer. Four reasons have been put forward as possible explanations: (i) Tobin effects, (ii) fiscal illusion, (iii) peso problems, and (iv) different estimators. Utilizing data on taxable and tax‐exempt bond interest rates and several different estimators, we find that the Fisher effect estimates are always larger for the taxable bond relative to the tax‐exempt bond, suggesting that fiscal illusion and different estimators cannot account for the previous results.
Banks and Corporate Control in Japan
Authors: Morck Randall , Nakamura Masao
Published: May 2003

Using a large sample of Japanese firm level data, we find that Japanese banks act primarily in the short term interests of creditors when dealing with firms outside bank groups. Corporate control mechanisms other than bank oversight appear necessary in these firms. When dealing with firms in bank groups, banks may act in the broader interests of a range of stakeholders, including shareholders. However, our findings are also consistent with banks “propping up” troubled bank group firms. We conclude that bank oversight need not lead to value maximizing corporate governance.
How Long Do Junk Bonds Spend in Default?
Authors: Helwege Jean
Published: May 2003

This paper analyzes junk bond defaults during 1980 to 1991 to determine which factors affect the length of time spent in default. Bondholder holdouts are not a significant problem, as firms with proportionately more bonds have shorter default spells. In contrast, bank debt is associated with slower restructurings. Bargaining problems arising from contingent liabilities, lawsuits, and size delay the process, although multiple bond classes do not. Neither information problems nor firm value appear to matter. HLTs do not resolve their defaults at a significantly faster pace. Defaults tend to take less time in the 1990s, despite Drexel's disappearance from the market.
Optimal Risk Management Using Options
Authors: Ahn Dong‐Hyun , Boudoukh Jacob , Richardson Matthew , Whitelaw Robert F.
Published: May 2003

This article provides an analytical solution to the problem of an institution optimally managing the market risk of a given exposure by minimizing its Value‐at‐Risk using options. The optimal hedge consists of a position in a single option whose strike price is independent of the level of expense the institution is willing to incur for its hedging program. This optimal strike price depends on the distribution of the asset exposure, the horizon of the hedge, and the level of protection desired by the institution. Moreover, the costs associated with a suboptimal choice of exercise price are economically significant.
Pricing Options under Generalized GARCH and Stochastic Volatility Processes
Authors: Ritchken Peter , Trevor Rob
Published: May 2003

In this paper, we develop an efficient lattice algorithm to price European and American options under discrete time GARCH processes. We show that this algorithm is easily extended to price options under generalized GARCH processes, with many of the existing stochastic volatility bivariate diffusion models appearing as limiting cases. We establish one unifying algorithm that can price options under almost all existing GARCH specifications as well as under a large family of bivariate diffusions in which volatility follows its own, perhaps correlated, process.
Determinants of the Consumer Bankruptcy Decision
Authors: Domowitz Ian , Sartain Robert L.
Published: May 2003

Qualitative choice models of consumers' decisions to file for bankruptcy and their choice of bankruptcy chapter are estimated jointly, combining choice‐based sampling techniques with a nested estimation procedure. Medical and credit card debt are found to be the strongest contributors to bankruptcy, with homeownership playing an important role with respect to both the decision to declare bankruptcy and the choice of bankruptcy alternative. The potential effects of legal changes relating to property exemptions and dischargeable debt categories are found to encourage debt repayment through Chapter 13.
Exact Isosurfaces for Marching Cubes
Authors: Theisel Holger
Published: May 2003

In this paper we study the exact contours of a piecewise trilinear scalar field. We show how to represent these contours exactly as trimmed surfaces of triangular rational cubic Bézier patches. As part of this, we introduce an extension of the marching cubes algorithm which gives a topologically exact triangular approximation of the contours for any case. Finally, we modify the exact contours to be globally G1 continuous without changing their topologies. We test the algorithm on both theoretical and practical data sets.
A Coherence‐based Collision Detection Method for Dressed Human Simulation
Authors: Zhang Dongliang , Yuen Matthew
Published: May 2003

In this paper, paper we present a coherence‐based method to detect collisions between the garment and human model for dressed human simulations. Based on the property of coherence, collisions can be rapidly detected by tracking the movement of the most likely geometric elements to collide. The voxel technique is employed to quickly identify the potential collision region. Experimental results show that our method is very efficient.
Web 2D Graphics File Formats
Authors: Duce David , Herman Ivan , Hopgood Bob
Published: May 2003

The earliest Web browsers focussed on the display of textual information. When graphics were added, essentially only image graphics and image file formats were supported. For a significant range of applications, image graphics has severe limitations, for example in terms of file size, download time and inability to interact with and modify the graphics client‐side. Vector graphics may be more appropriate in these cases, and this has become possible through the introduction of the WebCGM and Scalable Vector Graphics (SVG) formats, both of which are open standards, the former from ISO/IEC and W3C and the latter from W3C. This paper reviews the background to Web graphics, presents the WebCGM file format, and gives a more detailed exposition of the most recent format, SVG. The paper concludes with reflections on the current state of this area and future prospects.
Techniques for Realistic Visualization of Fluids: A Survey
Authors: Adabala Neeharika , Manohar Swami
Published: May 2003

Visualization of fluids has wide applications in science, engineering and entertainment. Various methodologies of visualizing fluids have evolved which emphasize on capturing different aspects of the fluids accurately. In this survey the existing methods for realistic visualization of fluids are reviewed. The approaches are classified based on the key concept they rely on for fluid modeling. This classification allows for easy selection of the method to be adopted for visualization given an application. It also enables identification of alternative techniques for fluid modeling.
Psychovisual Evaluation of Lossy CMYK Image Compression for Printing Applications
Authors: Denecker K. , De Neve P. , Van Assche S. , Van de Walle R. , Lemahieu I. , Philips W.
Published: May 2003

In the digital prepress workflow, images are represented in the CMYK colour space. Lossy image compression alleviates the need for high storage and bandwidth capacities, resulting from the high spatial and tonal resolution. After the image has been printed on paper, the introduced visual quality loss should not be noticeable to a human observer. Since visual image quality depends on the compression algorithm both quantitatively and qualitatively, and since no visual image quality models incorporating the end‐to‐end image reproduction process are satisfactory, an experimental comparison is the only viable way to quantify subjective image quality. This paper presents the results from an intensive psychovisual study based on a two‐alternative forced‐choice approach involving 164 people, with expert and non‐expert observers distinguished. The primary goal is to evaluate two previously published adaptations of JPEG to CMYK images, and to determine a visually lossless compression ratio threshold for typical printing applications. The improvements are based on tonal decorrelation and overlapping block transforms. Results on three typical prepress test images indicate that the proposed adaptations are useful and that for the investigated printing configuration, compression ratios up to 20 can be used safely.
Agency, place, scale: representations of inner‐city youth identities
Authors: Bauder Harald
Published: May 2003

Geographers are in a special position to comment on the role of neighbourhood representations in the marginalisation of urban minorities. This paper examines the impact of representations of place on the production of inner‐city youth identities. It argues that the spatial scale of representation is a crucial element in the production of marginal identity, and investigates whether switching scale is a viable option for escaping this identity. Linking the concepts of structure and agency to the notions of ideology and identity, it applies a theoretical argument to empirical contexts of representation and identity formation. Results from semi‐structured interviews with local youths and institutional administrators in an inner‐city neighbourhood of San Antonio, Texas, illustrate how place‐ and scale‐particular ideologies intervene in processes of youth identity formation. While overlying scales of place enables the social exclusion of youths, jumping scales does not empower individuals.
Spatial development initiatives in Southern Africa: The Maputo Development Corridor
Authors: Rogerson Christian M.
Published: May 2003

Spatial development initiatives (SDIs) are becoming a critical feature in the planning for reconstruction in post‐apartheid South (and Southern) Africa. The SDI programme marks a fundamental break with the trajectories and initiatives for economic and spatial planning of the apartheid past. The objective in this paper is to examine the record and developmental impact of SDI planning in South (ern) Africa through the lens of the most well‐known SDI, the Maputo Development Corridor or Maputo SDI. The cross‐border nature of the Maputo SDI makes it an important case study in terms of a recent shift in focus of the SDI programme towards a greater role for strengthening the regional Southern African economy. It is argued that the case of the Maputo SDI represents one illustration of the construction or configuring of a ‘new regionalism’ in Southern Africa.
What is Capital Flight?
Authors: Kant Chander
Published: May 2003

This paper offers a definitive distinction between capital flight and capital outflows. It unifies and synthesises the capital flight concept as used in both theoretical and empirical work and shows that various definitions have two common elements. These are: (1) capital flight is a subset of capital outflows from developing countries by its residents; (2) these outflows must be motivated by risks and uncertainties that are peculiar to developing countries. The former points to the counter‐intuitive nature of these outflows. The latter gives these counterintuitive outflows’ explanation. We then propose an econometric method to measure this concept, and illustrate its use by applying it to Korea.
Modelling the Impact of Environmental Regulations on Bilateral Trade Flows: OECD, 1990–1996
Authors: Harris Mark N. , Kónya László , Mátyás László
Published: May 2003

Since the early seventies an increasing attention has been paid to the impact environmental polict nmight have on foreign trade. One of the most important issues is whether countries with relatively strict environmental regulations tend to experience a deterioration of international competitiveness and thus a fall in exports and a rise in imports, of the pollution‐intensive commodities or, on the other hand, benefit from the improvement in environmentally more sensitive industries. So far, most empirical studies have concluded that the proportion of environmental costs to the total production costs is still so marginal that environmental policies have hardly any effect on comparative advantage patterns and thus on foreign trade. One of the few exceptions is Van Beers and Van den Bergh (1997), who found that stricter regulations have some negative impact on bilateral trade flows between OECD countries. The aim of this paper is to show that tyhis outcome is partly due to model mis‐specification. The analysis id based on a triple indexed model and on its variants. It is found that, as soon as both the importing and exporting country specific effects are taken into consideration, the relationship between stricter regulations and foreign trade becomes statistically insignificant. This suggests that environmental costs do not have a real impact, neither negative nor positive, on foreign trade.
Accession of the Czech Republic, Hungary and Poland to the European Union: Impacts on Agricultural Markets
Authors: Fuller Frank , Beghin John C. , Fabiosa Jacinto , Mohanty Samarendu , Fang Cheng , Kaus Phillip
Published: May 2003

We analyse the consequences on agricultural markets of enlargement of the European Union (EU) to include the Czech Republic, Hungary, and Poland. We produce a market outlook up to 2010 for two enlargement scenarios assuming different policy restrictions on grain and dairy production in the acceding countries. Accession of the three Central and Eastern European countries (CEECs) leads to a permanent but moderate decrease in EU prices for most commodities. In the three acceding CEECs, domestic prices increase drastically, final consumption of agricultural products decreases in most instances, while production increases. Higher domestic prices in the CEECs reduce exports of most commodities to non‐union countries. Consequently, excess supplies are placed in stocks or exported to the original 15 member countries. Supply management mechanisms in the dairy and grain sectors would reduce the build‐up of surpluses in the new member states, but limit their ability to take advantage of the expanded market. Accession of the three CEECs would increase the CAP budget over its proposed maximum if area payments are extended to incoming crop producers.
Inferences from DNA Data: Population Histories, Evolutionary Processes and Forensic Match Probabilities
Authors: Wilson Ian J. , Weale Michael E. , Balding David J.
Published: May 2003

We develop a flexible class of Metropolis–Hastings algorithms for drawing inferences about population histories and mutation rates from deoxyribonucleic acid (DNA) sequence data. Match probabilities for use in forensic identification are also obtained, which is particularly useful for mitochondrial DNA profiles. Our data augmentation approach, in which the ancestral DNA data are inferred at each node of the genealogical tree, simplifies likelihood calculations and permits a wide class of mutation models to be employed, so that many different types of DNA sequence data can be analysed within our framework. Moreover, simpler likelihood calculations imply greater freedom for generating tree proposals, so that algorithms with good mixing properties can be implemented. We incorporate the effects of demography by means of simple mechanisms for changes in population size and structure, and we estimate the corresponding demographic parameters, but we do not here allow for the effects of either recombination or selection. We illustrate our methods by application to four human DNA data sets, consisting of DNA sequences, short tandem repeat loci, single-nucleotide polymorphism sites and insertion sites. Two of the data sets are drawn from the male-specific Y-chromosome, one from maternally inherited mitochondrial DNA and one from the β-globin locus on chromosome 11.
Human Immunodeficiency Virus Risk: Is it Possible to Dissuade People from Having Unsafe Sex?
Authors: Richens John , Imrie John , Weiss Helen
Published: May 2003

The cumulative number of human immunodeficiency virus (HIV) infections worldwide has reached 60 million in little over 30 years. HIV continues to spread despite a detailed understanding of the manner in which it spreads and measures which can prevent spread. Some governments have been highly successful in containing the spread of HIV through blood products and from mother to child and among injecting drug users. Lack of political will, lack of resources or challenges to widely accepted scientific evidence have held back similar interventions in other countries. It has proved much more difficult to reduce the sexual transmission of HIV in both high and low income countries. A wide range of strategies has been identified but it remains unclear which strategies deserve priority and what methods of promoting them have the greatest effect. There is ample evidence that awareness of HIV and changes in sexual behaviour have occurred widely but the penetration of information remains poor in some vulnerable groups especially adolescents and women in poorer countries. Further obstacles face those who have information about the risk. The subordinate position of women and a desire for large families are important obstacles to condom negotiation and use. Urbanization, poverty, conflict and declining public services all exacerbate unsafe sexual behaviour. We argue that so-called ‘structural’ interventions directed at these wider contexts of unsafe behaviour merit greater attention. Such approaches have the added benefit of being less susceptible to ‘risk compensation’ which has the potential to undermine strategies directed at reducing the transmission efficiency of HIV.
Communicating Risk—Coronary Risk Scores
Authors: Graham Ian M. , Clavel Elizabeth
Published: May 2003

Cardiovascular disease, particularly heart attack and stroke, is the major cause of death in adults in Europe. The underlying atherosclerosis which causes cardiovascular disease is difficult to treat or reverse, and this has led to intense interest in strategies to prevent its development. The major causes of cardiovascular disease—a high fat diet, tobacco smoking and high blood pressure—are now well known. Control of these risk factors has been shown to reduce the risk of heart attack or stroke. It is now possible with simple information (age, sex, blood pressure level, cholesterol level and information on smoking) to predict the risk of heart attack or stroke fairly accurately. The challenge for the future is to make the information available on risk prediction and on how to reduce risk accessible to lay people, so that they may choose, if they wish, to adopt a life style that will reduce their risk. Such a life style involves healthy food choices, avoidance of overweight, the promotion of leisure exercise and complete avoidance of tobacco. Drug treatments can be extremely effective in controlling both blood pressure and cholesterol levels, but they should be seen as an adjunct to life style measures rather than a primary means of achieving prevention. Practical prevention will only be achieved through dynamic partnerships between the medical profession, Government, voluntary bodies, teaching institutions, insurance companies and paramedical bodies. An outline about how cardiac societies can participate in this process is appended.
Tobacco—The Importance of Relevant Information on Risk
Authors: Darby Sarah C.
Published: May 2003

Although it has been widely accepted since the 1960s that smoking cigarettes carries a substantial health risk, worldwide mortality from tobacco-related diseases is increasing rapidly at the beginning of the 21st century. To provide the motivation to control this epidemic there is a continuing and pressing need for information on the risks of tobacco consumption that is accurate, up to date, locally relevant and imaginatively presented.
Tobacco: Public Perceptions and the Role of the Industry
Authors: Simpson David , Lee Sue
Published: May 2003

The paper briefly examines the substantial risks of smoking, and how people's perception of them may be influenced by tobacco control policy and by the activities of the tobacco industry. The comparative lack of effectiveness of the self-regulation system of implementing tobacco control policy is noted, illustrated by the example of cigarette pack health warnings, from the first examples under the voluntary system to the significantly more robust and effective pictorial warnings system pioneered by Canada and implemented by legislation, similar to measures recently approved by the European Union. Other aspects of tobacco control policy are discussed, including health education, restricting the promotion of tobacco and changing the social acceptability of smoking. Three areas of success in the UK—taxation, the leadership of doctors and sustained media advocacy—are described; and the paper concludes by looking at prospects for the future, with the forthcoming ban on most forms of tobacco promotion and the challenge of responding to growing demands to protect non-smokers from exposure to other people's tobacco smoke in the workplace and in public places.
Communication of Risk: Health Hazards from Mobile Phones
Authors: Cox D. R.
Published: May 2003

Possible health hazards from mobile phones arise from the use of the phones themselves and via the base stations that relay signals. Except for an increase in traffic accidents induced by the use of mobile phones in cars the evidence for a health hazard is at most indirect, but it cannot be entirely dismissed; the phones have not been widely used for sufficiently long for direct epidemiological studies to have high sensitivity for detecting any induced incidence of cancer, for example. The background and evidence are briefly reviewed and the steps taken in the UK to make information widely available described.
Crime Victimization: Its Extent and Communication
Authors: Wiles Paul , Simmons Jon , Pease Ken
Published: May 2003

The criminal justice contexts are identified in which understanding and communicating risks are important. The paper is thereafter exclusively concerned with the probability of crime victimization classified by person and location. Examples of crime risks derived from the British Crime Survey are provided, with instances of where concern about crime diverges from risks of crime. Caution is advocated about seeking to reduce the fear of crime by reassurance. The high levels of concentration of crime by location are noted, together with the fact that particular individuals and households are repeatedly victimized, enabling the prioritization of crime-reductive resources after a crime has taken place. The paper concludes that an emphasis on how the supply of criminal opportunities may be regulated heralds a more systematic approach to the distribution of unavoidable hazard among citizens.
Accidental Fatalities in Transport
Authors: Evans Andrew W.
Published: May 2003

The paper considers accidents on the different modes of transport. Accidents have many kinds of unwanted effects, though the paper focuses on just one: accidental fatalities. The paper reviews the main official sources of accident data and considers the use of past accident data. It then offers data and discussion on the numbers of accidental fatalities per year, passenger fatality rates, major accidents and the fatalities imposed by transport on third parties. The paper concludes with a brief discussion of communicating these results.
Communicating the Risks Arising from Geohazards
Authors: Rosenbaum Michael S. , Culshaw Martin G.
Published: May 2003

Construction on, or in, the ground is affected by uncertainty. This includes the inherent variability of the ground itself, the effect of natural and human processes on the ground and the difficulties that are associated with the management and implementation of any construction works. The risk is considered to be in two parts: the probability of occurrence of a geohazard and the effect that this will have on the outcome of the project. Geohazards are determined as part of the ground investigation process, the principles of which are well established. Nevertheless uncertainty remains and communication between the professions and with the public is not always effective. Barriers are created by unfamiliar terminology and a lack of a forum for education and exchange of views. It is argued that the public must be continually involved—not only as recipients, but also as contributors.
Dimension Reduction for the Conditionalkth Moment in Regression
Authors: Yin Xiangrong , Cook R. Dennis
Published: May 2003

The idea of dimension reduction without loss of information can be quite helpful for guiding the construction of summary plots in regression without requiring a prespecified model. Central subspaces are designed to capture all the information for the regression and to provide a population structure for dimension reduction. Here, we introduce the central kth-moment subspace to capture information from the mean, variance and so on up to the kth conditional moment of the regression. New methods are studied for estimating these subspaces. Connections with sliced inverse regression are established, and examples illustrating the theory are presented.
A New Ranked Set Sample Estimator of Variance
Authors: MacEachern Steven N. , Öztürk Ömer , Wolfe Douglas A. , Stark Gregory V.
Published: May 2003

We develop an unbiased estimator of the variance of a population based on a ranked set sample. We show that this new estimator is better than estimating the variance based on a simple random sample and more efficient than the estimator based on a ranked set sample proposed by Stokes. Also, a test to determine the effectiveness of the judgment ordering process is proposed.
Posterior Probability Intervals for Wavelet Thresholding
Authors: Barber Stuart , Nason Guy P. , Silverman Bernard W.
Published: May 2003

We use cumulants to derive Bayesian credible intervals for wavelet regression estimates. The first four cumulants of the posterior distribution of the estimates are expressed in terms of the observed data and integer powers of the mother wavelet functions. These powers are closely approximated by linear combinations of wavelet scaling functions at an appropriate finer scale. Hence, a suitable modification of the discrete wavelet transform allows the posterior cumulants to be found efficiently for any given data set. Johnson transformations then yield the credible intervals themselves. Simulations show that these intervals have good coverage rates, even when the underlying function is inhomogeneous, where standard methods fail. In the case where the curve is smooth, the performance of our intervals remains competitive with established nonparametric regression methods.
On the Robustness of Weighted Methods for Fitting Models to Case–Control Edata
Authors: Scott Alastair , Wild Chris
Published: May 2003

We compare the robustness under model misspecification of two approaches to fitting logistic regression models with unmatched case–control data. One is the standard survey approach based on weighted versions of population estimating equations. The other is the likelihood-based approach that is standard in medical applications. The conventional view is that the (less efficient) survey-weighted approach leads to greater robustness. We conclude that this view is not always justified.
Publication Bias and Meta-Analysis for 2×2 Tables: An Average Markov Chain Monte Carlo EM Algorithm
Authors: Shi Jian Qing , Copas John
Published: May 2003

A major difficulty in meta-analysis is publication bias. Studies with positive outcomes are more likely to be published than studies reporting negative or inconclusive results. Correcting for this bias is not possible without making untestable assumptions. In this paper, a sensitivity analysis is discussed for the meta-analysis of 2×2 tables using exact conditional distributions. A Markov chain Monte Carlo EM algorithm is used to calculate maximum likelihood estimates. A rule for increasing the accuracy of estimation and automating the choice of the number of iterations is suggested.
Regression Model Selection—A Residual Likelihood Approach
Authors: Shi Peide , Tsai Chih-Ling
Published: May 2003

We obtain the residual information criterion RIC, a selection criterion based on the residual log-likelihood, for regression models including classical regression models, Box–Cox transformation models, weighted regression models and regression models with autoregressive moving average errors. We show that RIC is a consistent criterion, and that simulation studies for each of the four models indicate that RIC provides better model order choices than the Akaike information criterion, corrected Akaike information criterion, final prediction error, Cp and Radj2, except when the sample size is small and the signal-to-noise ratio is weak. In this case, none of the criteria performs well. Monte Carlo results also show that RIC is superior to the consistent Bayesian information criterion BIC when the signal-to-noise ratio is not weak, and it is comparable with BIC when the signal-to-noise ratio is weak and the sample size is large.
Econometric Analysis of Realized Volatility and its Use in Estimating Stochastic Volatility Models
Authors: Barndorff-Nielsen Ole E. , Shephard Neil
Published: May 2003

The availability of intraday data on the prices of speculative assets means that we can use quadratic variation-like measures of activity in financial markets, called realized volatility, to study the stochastic properties of returns. Here, under the assumption of a rather general stochastic volatility model, we derive the moments and the asymptotic distribution of the realized volatility error—the difference between realized volatility and the discretized integrated volatility (which we call actual volatility). These properties can be used to allow us to estimate the parameters of stochastic volatility models without recourse to the use of simulation-intensive methods.
Powerful Goodness-of-fit Tests Based on the Likelihood Ratio
Authors: Zhang Jin
Published: May 2003

A new approach of parameterization is proposed to construct a general goodness-of-fit test. It can not only generate traditional tests (including the Kolmogorov–Smirnov, Cramér–von Mises and Anderson–Darling tests) but also produce new types of omnibus tests, which are generally much more powerful than the old ones.
A Probabilistic Nearest Neighbour Method for Statistical Pattern Recognition
Authors: Holmes C. C. , Adams N. M.
Published: May 2003

Nearest neighbour algorithms are among the most popular methods used in statistical pattern recognition. The models are conceptually simple and empirical studies have shown that their performance is highly competitive against other techniques. However, the lack of a formal framework for choosing the size of the neighbourhood k is problematic. Furthermore, the method can only make discrete predictions by reporting the relative frequency of the classes in the neighbourhood of the prediction point. We present a probabilistic framework for the k-nearest-neighbour method that largely overcomes these difficulties. Uncertainty is accommodated via a prior distribution on k as well as in the strength of the interaction between neighbours. These prior distributions propagate uncertainty through to proper probabilistic predictions that have continuous support on (0, 1). The method makes no assumptions about the distribution of the predictor variables. The method is also fully automatic with no user-set parameters and empirically it proves to be highly accurate on many bench-mark data sets.
Spline Smoothing over Difficult Regions
Authors: Ramsay Tim
Published: May 2003

It is occasionally necessary to smooth data over domains in ℝ2 with complex irregular boundaries or interior holes. Traditional methods of smoothing which rely on the Euclidean metric or which measure smoothness over the entire real plane may then be inappropriate. This paper introduces a bivariate spline smoothing function defined as the minimizer of a penalized sum-of-squares functional. The roughness penalty is based on a partial differential operator and is integrated only over the problem domain by using finite element analysis. The method is motivated by and applied to two sample smoothing problems and is compared with the thin plate spline.