bluuebunny/crossref_metadata_2025 huggingface dataset:
Some recent finite volume schemes to compute Euler equations using real gas EOS
Authors: Gallouët T. , Hérard J.‐M. , Seguin N.
Published: August 2002

This paper deals with the resolution by finite volume methods of Euler equations in one space dimension, with real gas state laws (namely, perfect gas EOS, Tammann EOS and Van Der Waals EOS). All tests are of unsteady shock tube type, in order to examine a wide class of solutions, involving Sod shock tube, stationary shock wave, simple contact discontinuity, occurrence of vacuum by double rarefaction wave, propagation of a one‐rarefaction wave over ‘vacuum’, … Most of the methods computed herein are approximate Godunov solvers: VFRoe, VFFC, VFRoe ncv (τ, u, p) and PVRS. The energy relaxation method with VFRoe ncv (τ, u, p) and Rusanov scheme have been investigated too. Qualitative results are presented or commented for all test cases and numerical rates of convergence on some test cases have been measured for first‐ and second‐order (Runge–Kutta 2 with MUSCL reconstruction) approximations. Note that rates are measured on solutions involving discontinuities, in order to estimate the loss of accuracy due to these discontinuities. Copyright © 2002 John Wiley & Sons, Ltd.
On the validity of the perturbation approach for the flow inside weakly modulated channels
Authors: Zhou H. , Khayat R. E. , Martinuzzi R. J. , Straatman A. G.
Published: August 2002

The equations governing the flow of a viscous fluid in a two‐dimensional channel with weakly modulated walls have been solved using a perturbation approach, coupled to a variable‐step finite‐difference scheme. The solution is assumed to be a superposition of a mean and perturbed field. The perturbation results were compared to similar results from a classical finite‐volume approach to quantify the error. The influence of the wall geometry and flow Reynolds number have extensively been investigated. It was found that an explicit relation exists between the critical Reynolds number, at which the wall flow separates, and the dimensionless amplitude and wavelength of the wall modulation. Comparison of the flow shows that the perturbation method requires much less computational effort without sacrificing accuracy. The differences in predicted flow is kept well around the order of the square of the dimensionless amplitude, the order to which the regular perturbation expansion of the flow variables is carried out. Copyright © 2002 John Wiley & Sons, Ltd.
A novel finite point method for flow simulation
Authors: Cheng M. , Liu G. R.
Published: August 2002

A novel finite point method is developed to simulate flow problems. The mashes in the traditional numerical methods are supplanted by the distribution of points in the calculation domain. A local interpolation based on the properties of Taylor series expansion is used to construct an approximation for unknown functions and their derivatives. An upwind‐dominated scheme is proposed to efficiently handle the non‐linear convection. Comparison with the finite difference solutions for the two‐dimensional driven cavity flow and the experimental results for flow around a cylinder shows that the present method is capable of satisfactorily predicting the flow separation characteristic. The present algorithm is simple and flexible for complex geometric boundary. The influence of the point distribution on computation time and accuracy of results is included. Copyright © 2002 John Wiley & Sons, Ltd.
Accurate forecasting of the undecided population in a public opinion poll
Authors: Monterola Christopher , Lim May , Garcia Jerrold , Saloma Caesar
Published: August 2002

The problem of pollsters is addressed which is to forecast accurately the final answers of the undecided respondents to the primary question in a public opinion poll. The task is viewed as a pattern‐recognition problem of correlating the answers of the respondents to the peripheral questions in the survey with their primary answers. The underlying pattern is determined with a supervised artificial neural network that is trained using the peripheral answers of the decided respondents whose primary answers are also known. With peripheral answers as inputs, the trained network outputs the most probable primary response of an undecided respondent. For a poll conducted to determine the approval rating of the (former) Philippine president, J. E. Estrada in December 1999 and March 2000, the trained network predicted with a 95% success rate the direct responses of a test population that consists of 24.57% of the decided population who were excluded in the network training set. For the undecided population (22.67% of December respondents; 23.67% of March respondents), the network predicted a final response distribution that is consistent with the approval/disapproval ratio of the decided population. Copyright © 2002 John Wiley & Sons, Ltd.
Guesstimation
Authors: Charemza Wojciech W.
Published: August 2002

Macroeconomic model builders attempting to construct forecasting models frequently face constraints of data scarcity in terms of short time series of data, and also of parameter non‐constancy and underspecification. Hence, a realistic alternative is often to guess rather than to estimate parameters of such models. This paper concentrates on repetitive guessing (drawing) parameters from iteratively changing distributions, with the straightforward objective function being that of minimization of squares of ex‐post prediction errors, weighted by penalty weights and subject to a learning process. The examples are those of a Monte Carlo analysis of a regression problem and of a dynamic disequilibrium model. It is also an example of an empirical econometric model of the Polish economy. Copyright © 2002 John Wiley & Sons, Ltd.
A ground‐level ozone forecasting model for Santiago, Chile
Authors: Jorquera Héctor , Palma Wilfredo , Tapia José
Published: August 2002

A physically based model for ground‐level ozone forecasting is evaluated for Santiago, Chile. The model predicts the daily peak ozone concentration, with the daily rise of air temperature as input variable; weekends and rainy days appear as interventions. This model was used to analyse historical data, using the Linear Transfer Function/Finite Impulse Response (LTF/FIR) formalism; the Simultaneous Transfer Function (STF) method was used to analyse several monitoring stations together. Model evaluation showed a good forecasting performance across stations—for low and high ozone impacts—with power of detection (POD) values between 70 and 100%, Heidke's Skill Scores between 40% and 70% and low false alarm rates (FAR). The model consistently outperforms a pure persistence forecast. Model performance was not sensitive to different implementation options. The model performance degrades for two‐ and three‐days ahead forecast, but is still acceptable for the purpose of developing an environmental warning system at Santiago. Copyright © 2002 John Wiley & Sons, Ltd.
Portfolio managers' and novices' forecasts of risk and return: are there predictable forecast errors?
Authors: Muradog̃lu Gülnur
Published: August 2002

This study aims to investigate the individual behaviour that underlies the overreaction hypothesis by conducting a controlled experiment. Two areas that were not captured by previous research on the validity of the overreaction hypothesis are investigated. First, actual portfolio managers are employed as forecasters. Second a real‐world assessment task is given in the form of predicting the prices of stocks traded on the exchange on a real time basis. The purpose is to explore return expectations and risk perceptions of portfolio managers as well as financially unsophisticated investors by using point and interval forecasts provided for different forecast horizons in bull and bear markets. Contributions stem from three sources. (1) The use of financially sophisticated subjects for the first time in an experimental framework testing the overreaction hypothesis makes possible to control for the effect of expertise. (2) The use of different forecast horizons controls for the effect of forecast period. (3) The use of real‐time forecasts of specific stocks traded at the stock exchange, for the first time in an experimental framework testing the overreaction hypothesis enables to control for ecological validity. Discussions will be given as to the portfolio managers' versus naive investors' interpolating asset prices from past trends and hedging behaviour, due to their caution in projections of ranges for future prices. Copyright © 2002 John Wiley & Sons, Ltd.
Managing interdisciplinary health research–theoretical and practical aspects
Authors: Aagaard‐Hansen Jens , Henry Ouma John
Published: August 2002

Interdisciplinary health research can offer valuable evidence for health care managers. However, there are specific challenges regarding the management of such projects. Based on 7 years of experience from a project in western Kenya, the authors point to the need for a sufficient time horizon, a high level of communication, equity between the disciplines and the identification of appropriate evaluation criteria as issues to be considered. The theoretical framework of Rosenfield was modified to comply with the complexities of field management. Copyright © 2002 John Wiley & Sons, Ltd.
Markets for hospital services in Zambia
Authors: Nakamba Pamela , Hanson Kara , McPake Barbara
Published: August 2002

Hospital reforms involving the introduction of measures to increase competition in hospital markets are being implemented in a range of low and middle‐income countries. However, little is understood about the operation of hospital markets outside the USA and the UK. This paper assesses the degree of competition for hospital services in two hospital markets in Zambia (Copperbelt and Midlands), and the implications for prices, quality and efficiency. We found substantial differences among different hospital types in prices, costs and quality, suggesting that the hospital service market is a segmented market. The two markets differ significantly in their degree of competition, with the high cost inpatient services market in Copperbelt relatively more competitive than that in the Midlands market. The implications of these differences are discussed in terms of the potential for competition to improve hospital performance, the impact of market structure on equity of access, and how the government should address the problem of the mine hospitals. Copyright © 2002 John Wiley & Sons, Ltd.
Non‐invasive molecular detection of bladder cancer recurrence
Authors: Amira Najla , Mourah Samia , Rozet François , Teillac Pierre , Fiet Jean , Aubin Philippe , Cortesse Ariane , Desgrandchamps François , Le Duc Alain , Cussenot Olivier , Soliman Hany
Published: August 2002

Transitional cell carcinoma (TCC) is the most common bladder tumor and ≈90% of bladder TCC are superficial at initial diagnosis. High recurrence rate and possible progression to muscle invasive disease that is eventually indicated for radical cystectomy are established features of these tumors. Therefore, reliable predictors of tumor recurrence are of critical importance for management of superficial bladder TCC. Successful molecular diagnosis of bladder cancer by detecting genetic lesions: loss of heterozygosity (LOH) or microsatellite instability (MSI) in cells exfoliated in urine has been reported by several groups including ours. The aim of our study was to evaluate the predictive potential of microsatellite analysis of cells exfoliated in urine in the detection of superficial bladder TCC recurrence. We studied 47 Caucasian patients with confirmed superficial bladder TCC (37 pTa, 10 pT1) at initial diagnosis. Blood samples were obtained once from every patient whereas urine samples were collected before each cystoscopy (initial and follow‐up). Matched DNAs from blood and urine were subjected to microsatellite analysis in a blinded fashion. The follow‐up period ranged 12–48 months after tumor resection. Microsatellite analysis correctly identified 94% (44/47) of primary tumors and 92% (12/13) of tumor recurrences. Interestingly enough, 75% (9/12) of tumor recurrences were molecularly detected 1–9 months before cystoscopic evidence of recurrent disease. This study demonstrated clearly that not only urine microsatellite analysis reliably detected superficial bladder tumors, but also was a reliable test for detecting and predicting tumor recurrence in Caucasian patients. These results warrant multicenter randomized trials. © 2002 Wiley‐Liss, Inc.
Retracted: Impact of genomic instability in risk assessment and chemoprevention of oral premalignancies
Authors: Reith Albrecht , Sudbø Jon
Published: August 2002

Retraction: The following article from International Journal of Cancer, “Impact of genomic instability in risk assessment and chemoprevention of oral premalignancies”, by Albrecht Reith and Jon Sudbø, published online in Wiley InterScience (http://www3.interscience.wiley.com) on 31 July 2002 and in Volume 101, Number 3, pages 205‐209, has been retracted by agreement among author Albrecht Reith, the journal Editor in Chief, Peter Lichter, and Wiley Periodicals, Inc. The retraction has been agreed following an investigation conducted by the Rikshospitalet‐Radiumhospitalet MC and the University of Oslo into the work carried out by Jon Sudbø.
Monensin‐mediated growth inhibition in acute myelogenous leukemia cells via cell cycle arrest and apoptosis
Authors: Park Woo H. , Lee Myung S. , Park Keunchil , Kim Eun S. , Kim Byoung K. , Lee Young Y.
Published: August 2002

Monensin, an Na+ ionophore, regulates many cellular functions including apoptosis. However, there has been no report about the antitumoral effect of monensin on acute myelogenous leukemia (AML). Here, we investigated the antiproliferative effect of monensin on AML cells in vitro and in vivo. Monensin efficiently inhibited the proliferation of all of 10 AML cell lines, with IC50 of about 0.5 μM. DNA flow cytometric analysis indicated that monensin induced a G1 and/or a G2‐M phase arrest in these cell lines. To address the mechanism of the antiproliferative effect of monensin, we examined the effect of monensin on cell cycle‐related proteins in HL‐60 cells. The levels of CDK6, cyclin D1 and cyclin A were decreased. In addition, monensin not only increased the p27 level but also enhanced its binding with CDK2. Furthermore, the activities of CDK2‐ and CDK6‐associated kinases reduced by monensin were associated with hypophosphorylation of Rb protein. Monensin also induced apoptosis in AML cells including HL‐60 cells. The apoptotic process of HL‐60 cells was associated with changes in Bax, caspase‐3, caspase‐8 and mitochondria transmembrane potential (Δψm). In particular, monensin (i.p. at a dose of 8 mg/kg thrice weekly) significantly reduced the tumor size of BALB/c mice that were inoculated s.c. with its derived cell line, WEHI‐3BD cells (69% growth inhibition relative to control group; p < 0.05). Tumors from monensin‐treated mice exhibited increased apoptosis, and these tumor were immunohistochemically more stained with Bax, Fas and p53 antibodies than control tumors. In conclusion, this is the first report that monensin potently inhibits the proliferation of AML cells. © 2002 Wiley‐Liss, Inc.
Intratumoral injection of dendritic cells after treatment of anticancer drugs induces tumor‐specific antitumor effect in vivo
Authors: Tanaka Fumiaki , Yamaguchi Hiroshi , Ohta Mitsuhiko , Mashino Kohjiro , Sonoda Hideto , Sadanaga Noriaki , Inoue Hiroshi , Mori Masaki
Published: August 2002

We investigated the in vivo antitumor effects of intratumoral (i.t.) administration of dendritic cells (DC) after low‐dose chemotherapy using cisplatin + 5‐FU. Combination of i.t. injection of DC and systemic chemotherapy induced complete rejection of the treated tumor, MC38 murine adenocarcinoma. Furthermore, the antitumor effects were also observed on a distant tumor inoculated in the contralateral flank of the animal. When 10× the number of tumor cells were inoculated, the antitumor effect of the combination of DC after chemotherapy was also confirmed and in comparison to that of DC or chemotherapy alone, thereafter contributed to a greater prolongation of survival. To analyze the mechanisms of the systemic antitumor effect generated in this system, we assessed the cytolytic activity against inoculated tumors. The cytolytic activity of effector cells from treated animals was shown to be tumor‐specific and was mainly CD8 and MHC Class‐I (p < 0.01) restricted. CD4 and MHC Class‐II treatment marginally inhibited the cytolytic activity but not significantly (p = 0.07, 0.08 respectively). The cytolysis of effector cells was enhanced more significantly by the treatment of both DC and chemotherapy, than that of either DC or chemotherapy alone. Our study suggests that the strategy of i.t. injection of DC after low‐dose chemotherapy could be a powerful weapon to treat patients with cancer in the clinical settings. © 2002 Wiley‐Liss, Inc.
p53 status correlates with the differential expression of the DNA mismatch repair protein MSH2 in non‐small cell lung carcinoma
Authors: Xinarianos George , Liloglou Triantafillos , Prime Wendy , Sourvinos George , Karachristos Andreas , Gosney John R. , Spandidos Demetrios A. , Field John K.
Published: August 2002

We examined the p53 status of 108 NSCLCs compared to the expression of MLH1 and MSH2 proteins. p53 overexpression was demonstrated by IHC in 64% of patients examined, whereas p53 mutations were detected in 43%. Twenty‐two percent of mutations were located outside of the hot‐spot (exons 5–8) area. p53 mutations and overexpression were more frequent in SCCL (57% and 73%, respectively) than in lung adenocarcinomas (22% and 50%, respectively). In NSCLC‐carrying wild‐type p53, increased expression of MSH2 correlated with p53 overexpression (p = 0.018). In addition, in SCCL, p53 mutations correlated with reduced MSH2 expression (p = 0.019). These data suggest a relationship between p53 and MSH2. While there is evidence for p53 being a transcriptional activator of MSH2, the hypothesis that MSH2 acts as a DNA‐damage signaller triggering p53 overexpression needs to be clarified in future studies. © 2002 Wiley‐Liss, Inc.
Viruses and Hodgkin disease: No evidence of novel herpesviruses in non‐EBV‐associated lesions
Authors: Gallagher Alice , Perry Jacqueline , Shield Lesley , Freeland June , MacKenzie Jane , Jarrett Ruth F.
Published: August 2002

The Epstein‐Barr virus (EBV) is associated with a proportion of cases of Hodgkin disease (HD) and this association is believed to be causal. Epidemiological studies suggest that an infectious agent is involved in the aetiology of young adult HD, however, cases in this age group are less likely to have EBV‐associated disease than cases diagnosed in early childhood or older adult years. Molecular studies have failed to find a consistent association between HD and other candidate viruses, and the aetiology of non‐EBV‐associated cases remains obscure. We looked for evidence of herpesvirus infection in samples of non‐EBV‐associated HD using a highly sensitive, degenerate PCR assay. Despite exhaustive sequence analysis of PCR products, no novel herpesviruses were identified. These results suggest that it is extremely unlikely that a novel herpesvirus is involved in the pathogenesis of non‐EBV‐associated HD. © 2002 Wiley‐Liss, Inc.
Apoptotic body–loaded dendritic cells efficiently cross‐prime cytotoxic T lymphocytes specific for NA17‐A antigen but not for Melan‐A/MART‐1 antigen
Authors: Labarrière Nathalie , Bretaudeau Laurent , Gervois Nadine , Bodinier Marie , Bougras Gwenola , Diez Elisabeth , Lang François , Gregoire Marc , Jotereau Francine
Published: August 2002

DCs hold promise for cancer immunotherapy due to their functional ambivalence: iDCs internalize antigens, then mDCs trigger naive T‐cell activation. However, no consensus has been reached concerning the optimal mode of antigen acquisition for efficient cross‐priming of TAA‐specific CTLs, and this remains a field of investigation. Here, we used highly purified apobodies derived from an HLA‐A*0201‐negative melanoma line as a source of tumor antigens for HLA‐A*0201 DCs. We compared in vitro mDCs loaded with apobodies to DCs loaded with antigenic peptides, NA17‐A1–9 and Melan‐A/MART‐126–35 A27L analogue, for their capacity to stimulate melanoma antigen‐specific T cells from autologous PBLs. Apobody phagocytosis did not induce spontaneous DC maturation, but phagocytic DCs were still responsive to maturation signals, resulting in a functional ability to activate antigen‐specific lymphocytes. NA17‐A‐specific T lymphocytes were activated by both types of stimulation, whereas only peptide‐pulsed DCs stimulated the growth of Melan‐A/MART‐1‐specific lymphocytes. We also observed a lack of staining of melanoma‐derived apobodies with a Melan‐A‐specific MAb, suggesting protein alteration during apoptosis induction. After HLA‐A*0201/NA17‐A multimer sorting, antigen‐specific lymphocytes induced by mature DCs loaded with either peptide or apobodies displayed similar functional capacity against peptide‐pulsed T2 cells and melanoma cells. Therefore, apobody‐loaded DCs can achieve T‐cell priming similar to that induced by peptide‐pulsed DCs, provided that the apoptotic process allows the preservation of antigen expression. © 2002 Wiley‐Liss, Inc.
Autocrine motility factor secreted by tumor cells upregulates vascular endothelial growth factor receptor (Flt‐1) expression in endothelial cells
Authors: Funasaka Tatsuyoshi , Haga Arayo , Raz Avraham , Nagase Hisamitsu
Published: August 2002

The autocrine motility factor (AMF) is known as a cytokine regulating tumor cells motility via AMF receptor (AMFR) and promotes their metastasis. Recently, AMFRs have been found on the surface of host cells and it was showed that AMF possibly affects them. The signaling of AMF‐AMFR in the host endothelial cells induces expression of a vascular endothelial growth factor receptor (VEGFR) Flt‐1 and AMFR feedback that is regulated at the transcriptional level. AMF‐exposure stimulated the Flt‐1 expression on human umbilical vein endothelial cells (HUVECs) surface and this AMF‐treated cells exhibited high‐responsibility against VEGF. The protein kinase C (PKC) and phosphatidylinositol 3 kinase (PI3K) play an important role in this signal transduction. The findings of our study suggest the possibility of “tumor AMF→host AMFR→PKC, PI3K→→VEGFR or AMFR→angiogenesis, metastasis” as a new signal cross talk between the tumor and the host. © 2002 Wiley‐Liss, Inc.
Testing for causality‐in‐variance: an application to the East Asian markets
Authors: Caporale Guglielmo Maria , Pittis Nikitas , Spagnolo Nicola
Published: August 2002

In this paper we provide some empirical evidence on the casual relationship between stock prices and exchange rates volatility in four East Asian countries. In order to test for causality‐in‐variance, we use a GARCH model for which a BEKK representation is adopted, and then test for the relevant zero restrictions on the conditional variance parameters. We find that in the pre‐crisis sample stock prices lead exchange rates negatively in Japan and South Korea (consistently with the portfolio approach) and positively in Indonesia and Thailand. In the latter two countries after the onset of the 1997 East Asian crisis the spillover effects are found to be bidirectional. Copyright © 2002 John Wiley & Sons, Ltd.
Credit rationing for bad companies in bad years: evidence from bank loan transaction data
Authors: Shen Chung‐Hua
Published: August 2002

This paper examines whether or not there is equilibrium credit rationing using Taiwan banks loans' transaction data. Our transaction data are unique since they help us to identify the exact lenders and borrowers, thus reducing the aggregation bias. This paper raises three hypotheses to test equilibrium credit rationing. First, we argue that the loan supply should bend backward to be consistent with equilibrium credit rationing. Second, credit rationing is expected to be more severe in bad years than in good years, suggesting stronger asymmetric information during turbulent days. Third, the asymmetric information is more severe for bad companies than for good companies. Our results support almost all hypotheses except when a bad company is similarly credit rationed as a good company in bad years. Copyright © 2002 John Wiley & Sons, Ltd.
The economics of exchange rate volatility asymmetry
Authors: McKenzie Michael
Published: August 2002

One commonly observed feature of financial market volatility is the presence of asymmetry whereby shocks to the market do not generate equal responses. This phenomenon has been attributed to the leverage effect for stock markets. For exchange rates, asymmetry has also been documented with no economic reason apparent. In this paper, a hypothesis is proposed and tested which attributes the presence of asymmetric responses in exchange rate volatility to the intervention activity of the central bank. Using daily intervention data for the Reserve Bank of Australia, empirical evidence is presented in support of this hypothesis which suggests that intervention may do more harm than good in volatile markets. Copyright © 2002 John Wiley & Sons, Ltd.
Volatility linkages among interest rates: implications for global monetary policy
Authors: Laopodis Nikiforos T.
Published: August 2002

This paper explores the effects of a greater integration among major capital markets from 1984 to 2001 on the conduct of global monetary policy. The methodological design is a multivariate vector moving average GARCH model which is suitable for examining the nature of the volatility spillover mechanism of long‐term interest rates across markets. The empirical findings indicate that there have been stronger linkages among major bond markets since 1990 at the volatility level. The more synchronized behaviour of long‐term interest rates across countries is evidenced by the speed and persistence with which disturbances in a particular market transmit to other markets. Such volatile behaviour affects the conduct of global monetary policy which now has to be done interactively among the world's major players. Copyright © 2002 John Wiley & Sons, Ltd.
Spatial profiles in the analysis of event histories: an application to first sexual intercourse in Italy
Authors: Billari Francesco C. , Borgoni Riccardo
Published: August 2002

The aim of this paper is mainly methodological using individual‐level retrospective data from the Italian Fertility and Family Survey. Linking individual‐level data with geographical characteristics of the community, we firstly used non‐parametric methods, and in particular the bi‐dimensional LOESS (locally weighted regression) method, to build smoothed maps of the transition to first sexual intercourse. Secondly, we used a discrete‐time multilevel event‐history model (with logit specification), allowing for the presence of unobserved heterogeneity at the municipality level. We used ‘latitude’, ‘longitude’, and dimension of the municipality as aggregate‐level explanatory variables in the model. Thus, we could build spatial profiles and a map, using predicted values for the log‐odds‐ratio, and we could also study cohort dynamics. Our results confirm that Italy is a heterogeneous country; when looking at age at the first sexual intercourse, women are more influenced by their context than men. Copyright © 2002 John Wiley & Sons, Ltd.
Mining, migration and immobility: towards an understanding of the relationship between migration and occupation in the context of the UK mining industry
Authors: Hollywood Emma
Published: August 2002

The large‐scale decline of the UK mining industry in recent years has led to significant job losses, unemployment and inactivity throughout the coalfields. This paper aims to examine the role of migration as a response to these closures during the last 30 years. In neo‐classical economic theory, migration is traditionally seen as an equilibrating force in areas of labour‐market imbalance. However, this paper argues that migration is more closely associated with occupation than with imbalances in the demand and supply of labour, with professional workers displaying far higher rates of migration than manual workers. While migration is often seen as an integral part of many professional careers, by contrast it has little to do with the nature of manual occupations. Consequently, it is argued that the labour‐market problems faced by manual workers, such as miners, are unlikely to be alleviated by labour migration. In order to illustrate these arguments, the paper uses data from the Sample of Anonymised Records and the ONS Longitudinal Study. The migration rates of miners are compared with other occupational groups; migration rates over time are considered; and transitions in employment are examined. Copyright © 2002 John Wiley & Sons, Ltd.
Data mining using a genetic algorithm‐trained neural network
Authors: Sexton Randall S. , Sikander Naheel A.
Published: August 2002

Neural networks have been shown to perform well for mapping unknown functions from historical data in many business areas, such as accounting, finance, and management. Although there have been many successful applications of neural networks in business, additional information about the networks is still lacking, specifically, determination of inputs that are relevant to the neural network model. It is apparent that by knowing which inputs are actually contributing to model prediction a researcher has gained additional knowledge about the problem itself. This can lead to a parsimonious neural network architecture, better generalization for out‐of‐sample prediction, and, probably the most important, a better understanding of the problem. It is shown in this paper that by using a modified genetic algorithm for neural network training, relevant inputs can be determined while simultaneously searching for a global solution. Copyright © 2001 John Wiley & Sons, Ltd.
Executable declarative business rules and their use in electronic commerce
Authors: Antoniou G. , Arief M.
Published: August 2002

Business rules are statements which are used to run the activities of an organization. In the era of electronic commerce it is important for these rules to be represented explicitly, and to be automatically applicable. In this paper we argue that methods from the field of knowledge representation can be used for this purpose. In particular, we propose the use of defeasible reasoning, a simple but efficient reasoning method based on rules and priorities. We motivate the use of defeasible reasoning, give examples, describe two case studies, and outline current and future work in our research. Copyright © 2001 John Wiley & Sons, Ltd.
A data mining approach to financial time series modelling and forecasting
Authors: Vojinovic Zoran , Kecman Vojislav , Seidel Rainer
Published: August 2002

This paper describes one of the relatively new data mining techniques that can be used to forecast the foreign exchange time series process. The research aims to contribute to the development and application of such techniques by exposing them to difficult real‐world (non‐toy) data sets. The results reveal that the prediction of a Radial Basis Function Neural Network model for forecasting the daily $US/$NZ closing exchange rates is significantly better than the prediction of a traditional linear autoregressive model in both directional change and prediction of the exchange rate itself. We have also investigated the impact of the number of model inputs (model order), the number of hidden layer neurons and the size of training data set on prediction accuracy. In addition, we have explored how the three different methods for placement of Gaussian radial basis functions affect its predictive quality and singled out the best one. Copyright © 2001 John Wiley & Sons, Ltd.
Organizing and personalizing intelligence gathering from the web
Authors: Ong Hwee‐Leng , Tan Ah‐Hwee , Ng Jamie , Pan Hong , Li Qiu‐Xiang
Published: August 2002

In this paper, we describe how an integrated web‐based application, code‐named FOCI (Flexible Organizer for Competitive Intelligence), can help the knowledge worker in the gathering, organizing, tracking and dissemination of competitive intelligence (CI). It combines the use of a novel user‐configurable clustering, trend analysis and visualization techniques to manage information gathered from the web. FOCI allows its users to define and personalize the organization of the information clusters according to their needs and preferences into portfolios. These personalized portfolios created are saved and can be subsequently tracked and shared with other users. The paper runs through an example to show how the use of a predefined domain template coupled with personalization can greatly enhance an organization and tracking of CI gathered from the web. Copyright © 2002 John Wiley & Sons, Ltd.
Reorganizing web sites based on user access patterns
Authors: Fu Yongjian , Shih Ming‐Yi , Creado Mario , Ju Chunhua
Published: August 2002

In this paper, an approach for reorganizing Web sites based on user access patterns is proposed. Our goal is to build adaptive Web sites by evolving site structure to facilitate user access. The approach consists of three steps: preprocessing, page classification, and site reorganization. In preprocessing, pages on a Web site are processed to create an internal representation of the site. Page access information of its users is extracted from the Web server log. In page classification, the Web pages on the site are classified into two categories, index pages and content pages, based on the page access information. After the pages are classified, in site reorganization, the Web site is examined to find better ways to organize and arrange the pages on the site. An algorithm for reorganizing Web sites has been developed. Our experiments on a large real data set show that the approach is efficient and practical for adaptive Web sites. Copyright © 2002 John Wiley & Sons, Ltd.
Facilitating knowledge flow through the enterprise
Authors: Bruno Jeanette
Published: August 2002

This paper is concerned with the issues we encountered when attempting to achieve enterprise level knowledge reuse. We present three pilot studies where new visualization techniques were used to allow manufacturing and service operations take advantage of engineering knowledge embodied in 3D models. Though all these studies showed dramatic productivity increases, only one business unit from the studies is currently working to achieve the reuse. There are a number of reasons why this is so, but the key underlying theme is a lack of enterprise level commitment to knowledge sharing and a lack of an adequate knowledge architecture for sharing knowledge across organizational boundaries. We conclude with an approach for facilitating knowledge flow across functional units. Copyright © 2002 John Wiley & Sons, Ltd.
Censored latent effects autoregression, with an application to US unemployment
Authors: Franses Philip Hans , Paap Richard
Published: August 2002

A model is proposed to describe observed asymmetries in postwar unemployment time series data. We assume that recession periods, when unemployment increases rapidly, correspond with unobserved positive shocks. The generating mechanism of these latent shocks is a censored regression model, where linear combinations of lagged explanatory variables lead to positive shocks, while otherwise shocks are equal to zero. We apply this censored latent effects autoregression to monthly US unemployment, where the positive shocks are found to be predictable using various leading indicators. The model fits the data well and its out‐of‐sample forecasts appear to improve on those from alternative models. Copyright © 2002 John Wiley & Sons, Ltd.
A flexible parametric selection model for non‐normal data with application to health care usage
Authors: Prieger James E.
Published: August 2002

I examine the effects of insurance status and managed care on hospitalization spells, and develop a new approach for sample selection problems in parametric duration models. MLE of the Flexible Parametric Selection (FPS) model does not require numerical integration or simulation techniques. I discuss application to the exponential, Weibull, log‐logistic and gamma duration models. Applying the model to the hospitalization data indicates that the FPS model may be preferred even in cases in which other parametric approaches are available. Copyright © 2002 John Wiley & Sons, Ltd.
Geographic poverty traps? A micro model of consumption growth in rural China
Authors: Jalan Jyotsna , Ravallion Martin
Published: August 2002

How important are neighbourhood endowments of physical and human capital in explaining diverging fortunes over time for otherwise identical households in a developing rural economy? To answer this question we develop an estimable micro model of consumption growth allowing for constraints on factor mobility and externalities, whereby geographic capital can influence the productivity of a household's own capital. Our statistical test has considerable power in detecting geographic effects given that we control for latent heterogeneity in measured consumption growth rates at the micro level. We find robust evidence of geographic poverty traps in farm‐household panel data from post‐reform rural China. Our results strengthen the equity and efficiency case for public investment in lagging poor areas in this setting. Copyright © 2002 John Wiley & Sons, Ltd.
Socio‐economic distance and spatial patterns in unemployment
Authors: Conley Timothy G. , Topa Giorgio
Published: August 2002

This paper examines the spatial patterns of unemployment in Chicago between 1980 and 1990. We study unemployment clustering with respect to different social and economic distance metrics that reflect the structure of agents' social networks. Specifically, we use physical distance, travel time, and differences in ethnic and occupational distribution between locations. Our goal is to determine whether our estimates of spatial dependence are consistent with models in which agents' employment status is affected by information exchanged locally within their social networks. We present non‐parametric estimates of correlation across Census tracts as a function of each distance metric as well as pairs of metrics, both for unemployment rate itself and after conditioning on a set of tract characteristics. Our results indicate that there is a strong positive and statistically significant degree of spatial dependence in the distribution of raw unemployment rates, for all our metrics. However, once we condition on a set of covariates, most of the spatial autocorrelation is eliminated, with the exception of physical and occupational distance. Racial and ethnic composition variables are the single most important factor in explaining the observed correlation patterns. Copyright © 2002 John Wiley & Sons, Ltd.
Alcohol abuse and employment: a second look
Authors: Terza Joseph V.
Published: August 2002

Based on data from the 1988 Alcohol Supplement of the National Health Interview Survey, Mullahy and Sindelar (1996) (M&S) find, for both men and women, that alcohol abuse results in reduced employment and increased unemployment. The estimates from which they drew these inferences were obtained via the instrumental variables (IV) method, which was implemented in order to account for the potential endogeneity of problem drinking. Though these IV estimates qualitatively supported the prior expectation that problem drinking damages individuals' labour market prospects, they were not found to be statistically significant. The present paper revisits this research and offers a new estimation method which, in addition to accounting for endogeneity, explicitly allows for the inherent non‐linearity of the underlying regression structure. The new method is applied to the same data and variable specifications as those used by M&S for the male subpopulation. Consistent with their results, problem drinking is found to have a positive effect on the probability of unemployment and negative effect on the likelihood of being employed. Unlike their result, however, the latter estimate is statistically significant. An appealing feature of the new method is that it accommodates the likely possibility that alcohol abuse effects are heterogeneous with respect to the observed and unobserved characteristics of individuals in the population. To illustrate this fact, abuse effects are computed for two widely differing subgroups of the population. The large differential between the estimated effects for these two subpopulations demonstrates the potential importance of accounting for heterogeneity. Copyright © 2002 John Wiley & Sons, Ltd.
Parameterization of effective ice particle size for high‐latitude clouds
Authors: Boudala Faisal S. , Isaac George A. , Fu Qiang , Cober Stewart G.
Published: August 2002

A parameterization has been developed for mean effective size Dge in terms of ice water content (IWC) and temperature using in situ measurements of ice crystal spectra, cloud particle shapes and particle cross‐sectional area A from four research projects conducted in latitudes north of 45° N. The cloud microphysical measurements were made using PMS 2D optical probes, a PMS forward scattering spectrometer probe (FSSP), and Nevzorov total water and liquid water content probes. The IWCs derived from particle spectra using three different methods were compared with IWC measured with the Nevzorov probe (IWCNev). The contribution of small particles to the total mass was estimated by integrating a gamma distribution function that was fitted to match the measured FSSP concentrations. The Dge was calculated from the derived IWC and total cross‐sectional area per unit volume Ac.

This analysis indicates that there are significant differences among the schemes used to derive the IWC. It was found that the IWC derived based on the Cunningham scheme and IWCNev have the highest correlation: r2 = 0.78. After considering small particles, the derived IWC almost matched the IWCNev. The average estimated contribution of small particles to the Ac was 43%. The average estimated contribution of small particles to the total IWC, however, was 20%. Since Dge is directly proportional to the ratio IWC/Ac, the addition of small particles reduced the derived Dge considerably. The largest changes in Dge associated with small particles, however, occur at the coldest temperature and at low IWC, reaching up to 45% for temperatures less than −25° C. Generally, Dge and IWC increase with increasing temperature. Good agreement between the parameterized Dge and derived Dge from measurements were found when small particles were included. Copyright © 2002 Royal Meteorological Society.
Modelling carbon‐coupled energy and water dynamics of a boreal aspen forest in a general circulation model land surface scheme
Authors: Wang Shusen , Grant Robert F. , Verseghy Diana L. , Andrew Black T.
Published: August 2002

The ecosystem carbon (C) and nitrogen (N) processes and the C‐coupled energy and water dynamics were developed in the Canadian Land Surface Scheme (CLASS). The ecosystem C and N simulations include plant photosynthesis and respiration, plant tissue growth, senescence, root N uptake, soil heterotrophic respiration, and N mineralization and immobilization. These simulations are driven by variables (i.e. leaf temperature and water potential, and soil temperature and moisture) obtained from the C‐coupled energy and water balance simulations and feed back the model‐determined vegetation parameters (i.e. leaf area index, stomatal resistance, root length and distribution), which in turn control the land surface energy and water processes. In this paper, we introduce the C‐coupled energy and water balance scheme. The water flow process developed for the soil–plant–atmosphere system includes leaf and canopy stomatal resistance driven by leaf net CO2 fixation, plant water capacitance, and soil rhizosphere and plant root resistances. This water flow scheme is dynamically coupled with the canopy energy balance so that the full water balance and energy balance equations can be solved simultaneously. The model was run at a time step of 30 min and tested in a stand‐alone mode driven by meteorological observations obtained at the old aspen (Populus tremuloides) site in the southern study area of the Boreal Ecosystem–Atmosphere Study (BOREAS). Results show that the model reproduced the observed diurnal and seasonal patterns of energy fluxes fairly well. Canopy conductance in the mid‐growing season was simulated to reach above 0.5 mol m−2 s−1. Plant water capacitance was found to buffer the plant water flow process significantly and affect the canopy latent heat exchange under dry soil conditions. Comparisons of modelled and measured daily evapotranspiration in the two years of 1994 and 1996 gave the root‐mean‐square error of 0.71 mm day−1 and correlation coefficient of 0.75. Copyright © 2002 Royal Meteorological Society.
Predicting rainfall in the Dutch Caribbean—more than El Niño?
Authors: Martis Albert , van Oldenborgh Geert Jan , Burgers Gerrit
Published: August 2002

A strong lagged relationship between El Niño–Southern Oscillation (ENSO) and rainfall in the main rain season (October–January) on the leeward islands of Aruba, Curaçao and Bonaire is found. It can easily be used for skilful seasonal predictions, with an anomaly correlation coefficient r ≈ 0.6 at lag 4 months on historical data. The other two seasons, February–May and June–September, also show correlations with ENSO that can be exploited for predictions, r = 0.4 to 0.5. In the February–May dry season there is also a lagged correlation with sea‐surface temperature (SST) in the Pacific Ocean off the Central American coast that can be used to increase the forecast skill. A June–September small rains season correlation to equatorial Atlantic Ocean SST is absent in earlier data. Most of these results are also applicable to other stations in northern South America. Regressions with the circulation show that the main intermediate factors are upper‐level divergence and vorticity, and at lower levels a veering of the trade winds. This modifies the descending limb of the sea–continent breeze circulation that is responsible for the dry zone off the coast. Copyright © 2002 Royal Meteorological Society.