bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epistemologically authentic inquiry in schools: A theoretical framework for evaluating inquiry tasks
Authors: Chinn Clark A. , Malhotra Betina A. 
Published: August 2002

AbstractA main goal of science education is to help students learn to reason scientifically. A main way to facilitate learning is to engage students in inquiry activities such as conducting experiments. This article presents a theoretical framework for evaluating inquiry tasks in terms of how similar they are to authentic science. The framework helps identify the respects in which these reasoning tasks are similar to and different from real scientific research. The framework is based on a recent theory of reasoning, models‐of‐data theory. We argue that inquiry tasks commonly used in schools evoke reasoning processes that are qualitatively different from the processes employed in real scientific inquiry. Moreover, school reasoning tasks appear to be based on an epistemology that differs from the epistemology of authentic science. Inquiry tasks developed by researchers have increasingly captured features of authentic science, but further improvement is still possible. We conclude with a discussion of the implications of our analysis for research, assessment, and instruction. © 2002 Wiley Periodicals, Inc. Sci Ed 86:175–218, 2002; DOI 10.1002/sce.10001
“Peripheral and subversive”: Women making connections and challenging the boundaries of the science community
Authors: Davis Kathleen S. 
Published: August 2002

AbstractResearchers continue to report the underrepresentation of females in the science professions (AAUW, 1992; NSF, 1999; Vetter, 1992). Investigators have illuminated many factors that contribute to the insider status in the science community of some groups and the peripheral/outsider status of women and girls (Brickhouse, 1994; Delamont, 1989; Harding, 1991; Schiebinger, 1989). Some research has shown that supportive science networks have had a positive influence on women's participation and retention in science practices (AAUW, 1992; Keith & Keith, 1989; Kreinberg & Lewis, 1996; Varanka‐Martin, 1996). In order to provide a better understanding of the role social capital plays in women's legitimate participation in science, I draw upon the findings of a qualitative study that examines the valued capital, ways, and practices of a support group for women working in the sciences at an academic research institution. Findings from this study indicate how women 1) were given little access to powerful networks in science that would provide them with opportunities to acquire the knowledge, skills, and resources necessary to be legitimate in the traditional sense, and 2) encountered many obstacles in their attempts to develop networks and make such connections between themselves and other women. Findings also indicate that, despite these impediments, the support group provided a meaningful and resourceful network through which they developed a critical perspective of legitimacy as they sought to make explicit the “culture of science.” Participants not only employed the traditional methods of scientific inquiry, but also acknowledged and valued the voices and experiences of those from nondominant groups. They constructed a new discourse that was inclusive of diverse voices, created new career pathways, and developed a vision of mentoring that facilitated females' development of a critical view of the science community and their legitimate participation. © 2001 John Wiley & Sons, Inc. Sci Ed 85:368–409, 2001.
Measurement and control of business processes
Authors: Powell Stephen G. , Schwaninger Markus , Trimble Chris 
Published: August 2002

AbstractIt is widely accepted that any well‐designed organizational process includes a control mechanism through which management decides which aspects of the performance of the process are to be measured and how these measurements are to be used to change the level of resources utilized in the process. Little is known, however, about the best ways to design such a control mechanism for typical business processes. Our goal in this research is to identify control mechanisms for business processes that are effective in different types of environments. In this article we present a system dynamics model of a typical service‐sector business process, such as is used in processing administrative paperwork in insurance, banking, and so on. These processes are subject to random, time‐varying, and non‐postponable demands for service. They are also subject to randomness in processing times, as well as delays in the observation of system performance and in the execution of control actions. We assume management has the dual objectives of maximizing profits (revenues on completed work less the costs of labor employed) and keeping cycle times below a predetermined ceiling. In order to achieve these objectives it observes the state of the process and adjusts its labor force accordingly. Management must chose which of several aspects of process performance to measure (cycle time, backlog, or demand) and the parameters governing the control process. Our analysis highlights the interactions among the demand environment faced by the process (e.g., random or seasonal), the control signal chosen (e.g., cycle time or backlog), and the type of control used (e.g., proportional or differential). Our results suggest that, regardless of the demand environment, a control process based on system backlog is generally more robust than the alternatives in the sense that adequate performance is achieved over a broader range of control parameters. We also find that, in most cases, proportional control by itself is inadequate to provide effective performance and that differential control is a necessary adjunct. We conclude the article with a discussion of the managerial implications of this research. Copyright © 2001 John Wiley & Sons, Ltd.
Maps and models in system dynamics: a response to Coyle
Authors: Homer Jack , Oliva Rogelio 
Published: August 2002

AbstractGeoff Coyle has recently posed the question as to whether or not there may be situations in which computer simulation adds no value beyond that gained from qualitative causal‐loop mapping. We argue that simulation nearly always adds value, even in the face of significant uncertainties about data and the formulation of soft variables. This value derives from the fact that simulation models are formally testable, making it possible to draw behavioral and policy inferences reliably through simulation in a way that is rarely possible with maps alone. Even in those cases in which the uncertainties are too great to reach firm conclusions from a model, simulation can provide value by indicating which pieces of information would be required in order to make firm conclusions possible. Though qualitative mapping is useful for describing a problem situation and its possible causes and solutions, the added value of simulation modeling suggests that it should be used for dynamic analysis whenever the stakes are significant and time and budget permit. Copyright © 2001 John Wiley & Sons, Ltd.
The role of boundaries during superplastic deformation
Authors: Mohamed Farghalli A. 
Published: August 2002

AbstractMicrograin superplasticity refers to the ability of fine‐grained materials (d<10µm, where d is the grain size) to exhibit extensive neck‐free elongations during deformation at elevated temperatures (T>0.5Tm, where Tm is the melting point). Consideration of recent experimental data regarding the effects of impurities on the characteristics of micrograin superplasticity reveals an important role played by boundaries in superplastic alloys. This role pertains to the ability of boundaries to serve as favorable sites for the accumulation of impurities, i.e. boundary segregation. Evidence in support of boundary segregation during micrograin superplasticity is reviewed, with particular emphasis on creep behavior, cavitation, ductility, boundary sliding and the formation of cavity stringers. Copyright © 2001 John Wiley & Sons, Ltd.
Metal/ceramic interfaces: a microscopic analysis
Authors: Hosson Jeff Th. M. De , Kooi Bart J. 
Published: August 2002

AbstractThis contribution treats the fundamental and practical aspects of the analysis of interfaces between metals and ceramic materials. It is shown that, in principle at least, it is possible to assess the bond strength by investigating the atomic structure of the dislocation cores. We have chosen to exemplify our approach with the misfit‐dislocation structures at two, crystallographically different, systems, i.e. cube‐on‐cube and cube‐on‐non cube interfaces. It turns out that from high‐resolution transmission electron microscopy observations in combination with computer modelling studies a qualitative insight can be obtained about the bonding behaviour between these dissimilar materials. In general we may conclude that there is a fair correlation between the atomistic and linear elastic continuum description of interface dislocations. However, it is shown that the linear elastic continuum approach cannot account for the possible configurations at an interface with misfit, because it does not include the effects of different bonding strengths on the interface structure. This contribution directs also to some future experimental work. Segregation of other elements might affect the local bond strength which may become manifest in the experimental observations of atomic structure. Copyright © 2001 John Wiley & Sons, Ltd.
Light emission from surfaces, thin films and particles induced by high‐energy electron beam
Authors: Yamamoto N. , Araya K. , Toda A. , Sugiyama H. 
Published: August 2002

AbstractLight emission generated by a high‐energy electron passing through surfaces, thin films and particles of several materials were studied using a light detection system combined with a transmission electron microscope with an accelerating voltage of 200 kV. A silver film with a rough surface gives rise to inhomogeneous intensity distribution in the photon maps, which is due to the coupling of light with the non‐radiative surface plasmon mode through the surface roughness. In the case of a rough surface of a silver film with a granular structure, light is strongly emitted from a localized region with high polarization. The emissions from silver particles with various diameters were observed. The emission spectra show multiple peaks corresponding to the multipole modes of the electromagnetic oscillation in the spherical particle. The results can be explained well by the theory involving the retardation effect. Copyright © 2001 John Wiley & Sons, Ltd.
Individual patient‐ versus group‐level data meta‐regressions for the investigation of treatment effect modifiers: ecological bias rears its ugly head
Authors: Berlin Jesse A. , Santanna Jill , Schmid Christopher H. , Szczech Lynda A. , Feldman Harold I. 
Published: August 2002

AbstractWhen performing a meta‐analysis, interest often centres on finding explanations for heterogeneity in the data, rather than on producing a single summary estimate. Such exploratory analyses are frequently undertaken with published, study‐level data, using techniques of meta‐analytic regression. Our goal was to explore a real‐world example for which both published, group‐level and individual patient‐level data were available, and to compare the substantive conclusions reached by both methods. We studied the benefits of anti‐lymphocyte antibody induction therapy among renal transplant patients in five randomized trials, focusing on whether there are subgroups of patients in whom therapy might prove particularly beneficial. Allograft failure within 5 years was the endpoint studied. We used a variety of analytic approaches to the group‐level data, including weighted least‐squares regression (N=5 studies), logistic regression (N=628, the total number of subjects), and a hierarchical Bayesian approach. We fit logistic regression models to the patient‐level data. In the patient‐level analysis, we found that treatment was significantly more effective among patients with elevated (20 per cent or more) panel reactive antibodies (PRA) than among patients without elevated PRA. These patients comprise a small (about 15 per cent of patients) subgroup of patients that benefited from therapy. The group‐level analyses failed to detect this interaction. We recommend using individual patient data, when feasible, to study patient characteristics, in order to avoid the potential for ecological bias introduced by group‐level analyses. Copyright © 2002 John Wiley & Sons, Ltd.
Medical students' perspective on the teaching of medical statistics in the undergraduate medical curriculum
Authors: Astin Jeremy , Jenkins Tom , Moore Laurence 
Published: August 2002

AbstractTwo undergraduate medical students at the University of Bristol commented on their experiences of learning medical statistics. In general, medical students' focus is on acquiring skills needed to practice clinical medicine, and great care must be taken to explain why disciplines such as statistics and epidemiology are relevant to this. Use of real examples and an emphasis on the need for evidence has meant that medical students are increasingly aware of the pressure on clinicians to justify their treatment decisions, and the associated need to be able to understand and critically appraise medical research. It was felt that medical statistics courses should focus on critical appraisal skills rather than on the ability to analyse data, which can be acquired by particular students when they need to do this. Medical statistics should be taught early in the curriculum, but there is a need to reinforce such skills throughout the course. Teaching and assessment methods should recognize that what is being taught is a practical skill of clinical relevance. This means that problem based small groups, data interpretation exercises and objective structured clinical examinations will be more productive than traditional teaching and examination methods. Copyright © 2002 John Wiley & Sons, Ltd.
Accounting for correlation and compliance in cluster randomized trials
Authors: Loeys T. , Vansteelandt S. , Goetghebeur E. 
Published: August 2002

AbstractThis paper discusses causal inference with survival data from cluster randomized trials. It is argued that cluster randomization carries the potential for post‐randomization exposures which involve differentially selective compliance between treatment arms, even for an all or nothing exposure at the individual level. Structural models can be employed to account for post‐randomization exposures, but should not ignore clustering. We show how marginal modelling and random effects models allow to adapt structural estimators to account for clustering. Our findings are illustrated with data from a vitamin A trial for the prevention of infant mortality in the rural plains of Nepal. Copyright © 2001 John Wiley & Sons, Ltd.
Issues in the selection of a summary statistic for meta‐analysis of clinical trials with binary outcomes
Authors: Deeks Jonathan J. 
Published: August 2002

AbstractMeta‐analysis of binary data involves the computation of a weighted average of summary statistics calculated for each trial. The selection of the appropriate summary statistic is a subject of debate due to conflicts in the relative importance of mathematical properties and the ability to intuitively interpret results. This paper explores the process of identifying a summary statistic most likely to be consistent across trials when there is variation in control group event rates. Four summary statistics are considered: odds ratios (OR); risk differences (RD) and risk ratios of beneficial (RR(B)); and harmful outcomes (RR(H)). Each summary statistic corresponds to a different pattern of predicted absolute benefit of treatment with variation in baseline risk, the greatest difference in patterns of prediction being between RR(B) and RR(H). Selection of a summary statistic solely based on identification of the best‐fitting model by comparing tests of heterogeneity is problematic, principally due to low numbers of trials. It is proposed that choice of a summary statistic should be guided by both empirical evidence and clinically informed debate as to which model is likely to be closest to the expected pattern of treatment benefit across baseline risks. Empirical investigations comparing the four summary statistics on a sample of 551 systematic reviews provide evidence that the RR and OR models are on average more consistent than RD, there being no difference on average between RR and OR. From a second sample of 114 meta‐analyses evidence indicates that for interventions aimed at preventing an undesirable event, greatest absolute benefits are observed in trials with the highest baseline event rates, corresponding to the model of constant RR(H). The appropriate selection for a particular meta‐analysis may depend on understanding reasons for variation in control group event rates; in some situations uncertainty about the choice of summary statistic will remain. Copyright © 2002 John Wiley & Sons, Ltd.
Estimating equations for kappa statistics
Authors: Thompson John R. 
Published: August 2002

AbstractKappa statistics are often used for measuring agreement or association. The original measure suggested by Cohen for use with nominal data has since been generalized in a number of ways, including the incorporation of weights, adaptation for use with more than one rater and the application to bivariate data. Each modification requires a new approximation to the standard error and these have usually been derived by the delta method. This paper illustrates the use of estimating equations for kappa which offer a unified approach to many previously considered situations and which is also applicable to more complex designs. Copyright © 2001 John Wiley & Sons, Ltd.
Probabilistic population estimation of the size and overlap of data sets based on date of birth
Authors: Banks Steven M. , Pandiani John A. 
Published: August 2002

AbstractProbabilistic population estimation is a statistical procedure for deriving unduplicated counts of the number of people represented in data sets that do not include unique person identifiers and the number of people shared by data sets that do not share personal identifiers. Because the procedure relies on anonymous data sets, the personal privacy of individuals and the confidentiality of medical records is protected. This paper describes the mathematics of probabilistic population estimation, and applies the procedure to an important contemporary public policy issue. Copyright © 2001 John Wiley & Sons, Ltd.
A comparison of methods to detect publication bias in meta‐analysis
Authors: Macaskill Petra , Walter Stephen D. , Irwig Les 
Published: August 2002

AbstractMeta‐analyses are subject to bias for many of reasons, including publication bias. Asymmetry in a funnel plot of study size against treatment effect is often used to identify such bias. We compare the performance of three simple methods of testing for bias: the rank correlation method; a simple linear regression of the standardized estimate of treatment effect on the precision of the estimate; and a regression of the treatment effect on sample size. The tests are applied to simulated meta‐analyses in the presence and absence of publication bias. Both one‐sided and two‐sided censoring of studies based on statistical significance was used. The results indicate that none of the tests performs consistently well. Test performance varied with the magnitude of the true treatment effect, distribution of study size and whether a one‐ or two‐tailed significance test was employed. Overall, the power of the tests was low when the number of studies per meta‐analysis was close to that often observed in practice. Tests that showed the highest power also had type I error rates higher than the nominal level. Based on the empirical type I error rates, a regression of treatment effect on sample size, weighted by the inverse of the variance of the logit of the pooled proportion (using the marginal total) is the preferred method. Copyright © 2001 John Wiley & Sons, Ltd.
Sample size tables for exact single‐stage phase II designs
Authors: A'Hern R. P. 
Published: August 2002

AbstractTables for single‐phase II trials based on the exact binomial distribution are presented. These are preferable to those generated using Fleming's design, which are based on the normal approximation and can give rise to anomalous results. For example, if the upper success rate is accepted, the lower success rate, which the trial is designed to reject, may be included in the final confidence interval for the proportion being estimated. Copyright © 2001 John Wiley & Sons, Ltd.
Estimating cohort health expectancies from cross‐sectional surveys of disability
Authors: Davis B. A. , Heathcote C. R. , O'Neill T. J. 
Published: August 2002

AbstractA life history can be regarded as a random process that evolves with age through various states of health before terminating with absorption into the state of death. Health expectancies are the occupation times of the non‐absorbing states and their estimation is of interest. A continuing major problem has been the lack of satisfactory longitudinal data on which to base estimates and as a result standard inferential techniques may not be relevant. Supposing only cross‐sectional data available, we propose a method that is generally applicable and first estimates a logistic parametrization of the probabilities of the various states. A large sample approximation is obtained for the distribution of age specific log (odds). Parameters are estimated by weighted least squares, and this in turn leads to estimates of cohort health expectancies. A result of Liang and Zeger is used to find standard errors. The method is illustrated by application to Australian data from the health surveys of 1981, 1988 and 1993. Copyright © 2001 John Wiley & Sons, Ltd.
The continual reassessment method and its applications: a Bayesian methodology for phase I cancer clinical trials
Authors: Ishizuka Naoki , Ohashi Yasuo 
Published: August 2002

AbstractWe discuss the continual reassessment method (CRM) and its extension with practical applications in phase I and I/II cancer clinical trials. The CRM has been proposed as an alternative design of a traditional cohort design and its essential features are the sequential (continual) selection of a dose level for the next patients based on the dose–toxicity relationship and the updating of the relationship based on patients' response data using Bayesian calculation. The original CRM has been criticized because it often tends to allocate too toxic doses to many patients and our proposal for overcoming this practical problem is to monitor a posterior density function of the occurrence of the dose limiting toxicity (DLT) at each dose level. A simulation study shows that strategies based on our proposal allocate a smaller number of patients to doses higher than the maximum tolerated dose (MTD) compared with the original method while the mean squared error of the probability of the DLT occurrence at the MTD is not inflated. We present a couple of extensions of the CRM with real prospective applications: (i) monitoring efficacy and toxicity simultaneously in a combination phase I/II trial; (ii) combining the idea of pharmacokinetically guided dose escalation (PKGDE) and utilization of animal toxicity data in determining the prior distribution. A stopping rule based on the idea of separation among the DLT density functions is discussed in the first example and a strategy for determining the model parameter of the dose–toxicity relationship is suggested in the second example. Copyright © 2001 John Wiley & Sons, Ltd.