bluuebunny/crossref_metadata_2025 huggingface dataset:
Sonographic Features of Cystic Papillary Carcinoma of the Thyroid
Authors: Dineen Robert , Robinson Ivan , Cozens Neil
Published: August 2005

Cystic changes are a well-recognized finding in papillary carcinoma of the thyroid, being described in 10–30% of cases. Much less commonly, cystic changes predominate and the diagnosis of malignancy can be difficult. Differentiation between extremely common benign cystically degenerate hyperplastic nodules and the rare entity of cystic papillary carcinoma can be difficult. In this pictorial review we consider five cases of cystic papillary carcinoma and highlight the ultrasound features, which should alert the sonographer to the possibility of this diagnosis. The role of fine needle aspiration cytology in these difficult cases is discussed, as is the potential for recommending surgery based on the ultrasound features.
Report on the BMUS Pump Priming Award 2003: Measurement of Velocities and Shear Stresses at the Surface of Endothelial Cells in an In Vitro Model
Authors: Moran Carmel M. , Butler Mairead B.
Published: August 2005

Identification of characteristics of plaque in areas of disruption and cellular inflammation is critical in understanding the pathogenesis of acute coronary syndromes. However, techniques aimed at identifying vulnerable or inflamed plaques are not routinely available for use in vivo. In a novel approach, funded by the British Heart Foundation, we have developed lipid-based microbubbles with echogenicity at 40 MHz similar to that of commercial agents and we have conducted preliminary studies demonstrating that it is feasible to attach specific antibodies to their surfaces. We have also demonstrated that these antibody-loaded microbubbles bind to cell surfaces and that the resultant increase in echogenicity can be detected using high frequency ultrasound. However such results have been undertaken under no-flow conditions where the cells are grown on agar plugs and the microbubbles are attached to them in situ. By extending this work into a flow chamber and obtaining high resolution velocity patterns it will be possible to quantify the strength of the binding mechanisms between the microbubbles and cells. For this purpose, we applied to the British Medical Ultrasound Society for a pump-priming award to purchase a lens for a Laser Doppler Anemometry system, which could be used to obtain high-resolution velocity measurements within a prototype flow chamber. From these measurements the shear rate and, hence, shear stress at the surface of the agar plugs within the flow chamber could be calculated.
Does Patient Ethnicity or Sonographer Gender Have Any Bearing on Patient Acceptability of Transvaginal Ultrasound?
Authors: Russell Mark
Published: August 2005

Transvaginal ultrasound scanning (TVS) has become the first line radiological investigation of the female pelvis in many hospitals. Previous research looking at patient acceptability of this technique rarely includes any reference to male sonographers or patient ethnicity. The aim of this study was to assess whether these factors had any bearing on patient acceptability of TVS. The study was carried out in an inner city hospital serving a large multi-ethnic population and employing several male sonographers. A simple questionnaire was completed by 147 patients who had both transabdominal (TA) and transvaginal ultrasound (TV) examinations at the time of their appointment. The study found general acceptability of TVS to be high, with 99.3% of patients who would have it again if their doctor suggested it. Acceptability also increased with respondent age and if previously pregnant. Overall, 70.1% of respondents were willing to be scanned transvaginally by a male sonographer with a female chaperone present. Variation was shown here between ethnic groups with 81% in the white Caucasian group and 58.3% in the Turkish group. This was not statistically significant. None of the white Caucasian group had any religious/cultural objections to being examined by a male practitioner compared with 25% of the Turkish group and 23% of the mixed 'Other' group. Limitations of the study included its sample size, especially of some of the ethnic groups. Some groups were combined to analyse the data, which resulted in the loss of specific information. A larger multicentre study is recommended to overcome these problems.
The Need for Evidence-Based Quality Assurance in the Modern Ultrasound Clinical Laboratory
Authors: Wayne Moore G. , Gessert Amanda , Schafer Mark
Published: August 2005

A quick review of the specification sheets for new technologically intensive diagnostic ultrasound systems reveals a substantial number of fairly impressive operational performance claims. In at least one manufacturer's published material, the system specifications boasts of a dynamic range of 180 dB. To put that number in perspective, a device capable of 180 dB of dynamic range of resolution would be able to detect the flutter of a butterfly's wing in the middle of a thermonuclear explosion. How does one verify such an astounding performance claim using currently available ultrasound testing devices such as a tissue-mimicking phantom and what is the explicit clinical significance of such dynamic range? Additionally, while most of us were focused with amazement in leapfrog advances in system technology, diagnostic ultrasound transducers were also undergoing radical changes in array material composition and design. Most modern composite transducer specifications claim fractional bandwidths of 85%, and more and element counts as high as 2500. While the great technological strides made in ultrasound system design have been impressive, all of the computational and processing power of the 'all-digital' ultrasound device is singularly dependent on the output and input characteristics of the ultrasound transducer. Published data shows that the ultrasound transducer is subject to degradation in performance, as well as element failure, potentially leading to patient misdiagnosis or under-diagnosis. The need to regularly test transducers for performance variances will be explored within this paper. Additionally, the key areas of transducer performance as they relate to image and Doppler quality will be defined.
Antenatal Detection of Heart Defects is Important and Achievable
Authors: Gardiner Helena M.
Published: August 2005

Congenital heart disease occurs in about 1 in 125 live births, approximately half of which require urgent evaluation and management. Cardiovascular malformations account for 10% of infant deaths and nearly half of all deaths from all malformations. They are, therefore, both important and common, but are still frequently missed in primary screening programmes worldwide. The UK average detection rate is 23% with wide postcode variation. The reasons for missing defects are difficult to ascertain. However, with 'hands-on' training of obstetric sonographers in their own unit, detection levels may increase to 70–80%. With ongoing support these levels are sustainable. This 'hands-on' training uses a systematic protocol, the five transverse views, which allows the majority of defects to be detected at the routine 20-week scan without increasing routine examination time.
Evidence for ineffective erythropoiesis in severe sickle cell disease
Authors: Wu Catherine J. , Krishnamurti Lakshamanan , Kutok Jeffery L. , Biernacki Melinda , Rogers Shelby , Zhang Wandi , Antin Joseph H. , Ritz Jerome
Published: August 2005

Peripheral destruction of sickled erythrocytes is a cardinal feature of sickle cell disease (SCD). Less well established is the potential contribution of ineffective erythropoiesis to the pathophysiology of this hemoglobinopathy. Since patients with SCD frequently develop mixed hematopoietic chimerism after allogeneic nonmyeloablative stem cell transplantation, we used this opportunity to directly compare the differentiation and survival of SCD and donor-derived erythropoiesis in vivo. Donor and recipient erythropoiesis was compared in 4 patients with SCD and 4 without SCD who developed stable mixed hematopoietic chimerism following transplant. Molecular analysis of chimerism in peripheral blood and bone marrow demonstrated higher expression of donor-derived β-globin RNA relative to the level of donor-derived genomic DNA in patients with SCD. Analysis of chimerism in immature (glycophorin A–positive [GYPA+], CD71hi) and mature (GYPA+, CD71neg) erythroblasts confirmed the intramedullary loss of SS erythroblasts with progressive maturation. In patients with SCD, relative enrichment of donor erythroid precursors began to appear at the onset of hemoglobinization. Ineffective erythropoiesis of homozygous hemoglobin S (SS) progenitors thus provides a maturation advantage for homozygous hemoglobin A (AA) or heterozygous hemoglobin S/hemoglobin A (SA) donor erythroid precursor cells that results in greater donor contribution to overall erythropoiesis following stem-cell transplantation and improvement of clinical disease.
Cell of origin, germinal center versus nongerminal center, determined by immunohistochemistry on tissue microarray, does not correlate with outcome in patients with relapsed and refractory DLBCL
Authors: Moskowitz Craig H. , Zelenetz Andrew D. , Kewalramani Tarun , Hamlin Paul , Lessac-Chenen Simone , Houldsworth Jane , Olshen Adam , Chaganti Raju , Nimer Stephen , Teruya-Feldstein Julie
Published: August 2005

A number of prognostic factors affect outcome in patients with relapsed or primary refractory diffuse large B-cell lymphoma (DLBCL), including refractory disease and the second-line age-adjusted international prognostic index. In de novo DLBCL, the cell of orgin, as determined by expression microarray analysis or immunohistochemistry (IHC), predicts event-free survival (EFS). We evaluated the cell of origin, as well as other pathologic markers of outcome, on the repeat biopsy specimen of 88 transplantation-eligible patients undergoing ifosfamide, carboplatin, etoposide (ICE) second-line chemotherapy (SLT) followed by high-dose therapy (HDT) and autologous stem cell transplantation (ASCT) to see if were they prognostic in the salvage setting. Pretreatment clinical factors were well balanced between the cohorts. There was no significant difference in response to SLT, HDT, event-free or overall survival based on the cell of origin or any of the common pathologic markers examined. The cell of origin as determined by IHC does not predict outcome in transplantation-eligible patients with relapsed or primary refractory DLBCL.
A systematic search for new mammalian noncoding RNAs indicates little conserved intergenic transcription
Authors: Babak Tomas , Blencowe Benjamin J , Hughes Timothy R
Published: August 2005

Background

Systematic identification and functional characterization of novel types of noncoding (nc)RNA in genomes is more difficult than it is for protein coding mRNAs, since ncRNAs typically do not possess sequence features such as splicing or translation signals, or long open reading frames. Recent "tiling" microarray studies have reported that a surprisingly larger proportion of mammalian genomes is transcribed than was previously anticipated. However, these non-genic transcripts often appear to be low in abundance, and their functional significance is not known.

Results

To systematically search for functional ncRNAs, we designed microarrays to detect 3,478 intergenic and intronic sequences that are conserved between the human, mouse, and rat genomes, and that score highly by other criteria that characterize ncRNAs. We probed these arrays with total RNA isolated from 16 wild-type mouse tissues. Among 55 candidates for highly-expressed novel ncRNAs tested by northern blotting, eight were confirmed as small, highly-and ubiquitously-expressed RNAs in mouse. Of the eight, five were also detected in rat tissues, but none were detected at appreciable levels in human tissues or cultured cells.

Conclusion

Since the sequence and expression of most known coding transcripts and functional ncRNAs is conserved between human and mouse, the lack of northern-detectable expression in human cells and tissues of the novel mouse and rat ncRNAs that we identified suggests that they are not functional or possibly have rodent-specific functions. Our results confirm that relatively little of the intergenic sequence conserved between human, mouse and rat is transcribed at high levels in mammalian tissues, possibly suggesting a limited role for transcribed intergenic and intronic sequences as independent functional elements.
Genetic polymorphism of the N-acetyltransferase 2 gene, and susceptibility to prostate cancer: a pilot study in north Indian population
Authors: Srivastava Daya SL , Mittal Rama D
Published: August 2005

Background

N-acetyltransferase 2 is phase II metabolizing enzyme that participates in the bioconversion of heterocyclic arylamines into electrophilic nitrenium ions, which are important ultimate carcinogens that are directly implicated in tumor initiation process. This study was conducted to examine; (1) whether the N-acetyltransferase 2 (NAT2) genotype is a risk factor for prostate cancer, (2) to study effect of NAT2 genotype on modifying prostate cancer risk from tobacco use.

Methods

The case control study was undertaken over a period of 28 months and included 130 prostate cancer patients (CaP) and 140 controls. The NAT2 genotypes were identified by PCR-RFLP method in DNA extracted from peripheral blood. Genotype frequencies and the association of genotypes with patients and control groups were assessed by logistic regression model.

Results

We observed non-significant association of rapid acetylator genotype NAT2 (OR = 1.452, 95% CI: 0.54–1.87,P= 0.136) in prostate cancer patients. However significant association was observed between rapid acetylator genotype NAT2 and CaP tobacco users (OR = 3.43, 95% CI: 1.68–7.02,P-value < 0.001) when compared with controls.

Conclusion

The data suggests that the NAT2 rapid acetylator genotypes may play an important role in determining the risk of developing prostate cancer particularly in the tobacco users of north Indian population.
Need for enforcement of ethicolegal education – an analysis of the survey of postgraduate clinical trainees
Authors: Mayeda Mayumi , Takase Kozo
Published: August 2005

Background

The number of medical lawsuits in Japan was between 14 and 21 each year before 1998, but increased to 24 to 35 per year after 1999. There were 210 lawsuits during this 10-year period. There is a need for skills and knowledge related to ethics, which is as fundamental to the practice of medicine as basic sciences or clinical skills. in Japan education in ethics is relatively rare and its importance is not yet recognized. Establishing ethics education using legal precedents, which has already been achieved in Western countries, will be a very important issue in Japan. In the present study, a questionnaire survey was conducted among graduate intern doctors, in order to investigate whether ethics education using precedents might have a positive effect in Japan.

Methods

In 2002, a questionnaire survey entitled Physicians' Clinical Ethics was carried out in a compulsory orientation lecture given to trainees before they started clinical practice in our hospital. The attendees at this lecture were trainees who came from colleges in various districts of Japan. During the lecture, 102 questionnaires were distributed, completed by attendees and collected. The recovery rate was 100%. The questionnaire consisted of 22 questions (in three categories), of which 20 were answered by multiple choices, and the other two were answered by description. The time required to complete the questionnaire was about 10 minutes.

Results

The recovered questionnaires were analyzed using statistical analysis software (SPSS for Windows, Release 10.07J-1/June/2000), in addition to simple statistical analysis. answers using multiple choices for the 20 questions in the questionnaire were input into SPSS. The principal component analysis was performed for each question. As a result, the item that came to the fore was "legal precedent". Since many intern doctors were interested in understanding laws and precedents, learning about ethical considerations through education using precedents might better meet with their needs and interests.

Conclusion

We applied a new method in which the results of principal component analysis and frequencies of answers to other questions were combined. From this we deduced that the precedent education used in Western countries was useful to help doctors acquire ethical sensitivity and was not against their will. A relationship was found between reading precedents and the influence of lawsuits, and it was thought that student participation-type precedent education would be useful for doctors in order to acquire ethical sensitivity.
Predictors of failed attendances in a multi-specialty outpatient centre using electronic databases
Authors: Lee Vernon J , Earnest Arul , Chen Mark I , Krishnan Bala
Published: August 2005

Background

Failure to keep outpatient medical appointments results in inefficiencies and costs. The objective of this study is to show the factors in an existing electronic database that affect failed appointments and to develop a predictive probability model to increase the effectiveness of interventions.

Methods

A retrospective study was conducted on outpatient clinic attendances at Tan Tock Seng Hospital, Singapore from 2000 to 2004. 22864 patients were randomly sampled for analysis. The outcome measure was failed outpatient appointments according to each patient's latest appointment.

Results

Failures comprised of 21% of all appointments and 39% when using the patients' latest appointment. Using odds ratios from the mutliple logistic regression analysis, age group (0.75 to 0.84 for groups above 40 years compared to below 20 years), race (1.48 for Malays, 1.61 for Indians compared to Chinese), days from scheduling to appointment (2.38 for more than 21 days compared to less than 7 days), previous failed appointments (1.79 for more than 60% failures and 4.38 for no previous appointments, compared with less than 20% failures), provision of cell phone number (0.10 for providing numbers compared to otherwise) and distance from hospital (1.14 for more than 14 km compared to less than 6 km) were significantly associated with failed appointments. The predicted probability model's diagnostic accuracy to predict failures is more than 80%.

Conclusion

A few key variables have shown to adequately account for and predict failed appointments using existing electronic databases. These can be used to develop integrative technological solutions in the outpatient clinic.
Embodiment in Attitudes, Social Perception, and Emotion
Authors: Niedenthal Paula M. , Barsalou Lawrence W. , Winkielman Piotr , Krauth-Gruber Silvia , Ric François
Published: August 2005

Findings in the social psychology literatures on attitudes, social perception, and emotion demonstrate that social information processing involves embodiment, where embodiment refers both to actual bodily states and to simulations of experience in the brain's modality-specific systems for perception, action, and introspection. We show that embodiment underlies social information processing when the perceiver interacts with actual social objects (online cognition) and when the perceiver represents social objects in their absence (offline cognition). Although many empirical demonstrations of social embodiment exist, no particularly compelling account of them has been offered. We propose that theories of embodied cognition, such as the Perceptual Symbol Systems (PSS) account (Barsalou, 1999), explain and integrate these findings, and that they also suggest exciting new directions for research. We compare the PSS account to a variety of related proposals and show how it addresses criticisms that have previously posed problems for the general embodiment approach.
An Integrated Review of Indirect, Relational, and Social Aggression
Authors: Archer John , Coyne Sarah M.
Published: August 2005

Over the last decade, researchers have found that girls may be just as aggressive as boys when manipulative forms of aggression, such as gossiping and spreading rumors, are included. These forms of aggression are known by 3 different names: indirect aggression, relational aggression, and social aggression. This review examines their commonalities and differences, and concludes that they are essentially the same form of aggression. We show that analogous forms are not found in other species. We offer a functional account: indirect aggression is an alternative strategy to direct aggression, enacted when the costs of direct aggression are high, and whose aim is to socially exclude, or harm the social status of, a victim. In this light, we consider sex differences and developmental trends and the impact of this aggression on victims. We conclude that indirect, relational, and social aggression are much more similar than they are different, and we suggest ways in which future research can be facilitated by integrating the three areas under an adaptive framework.
A Connectionist Model of Attitude Formation and Change
Authors: Van Overwalle Frank , Siebler Frank
Published: August 2005

This article discusses a recurrent connectionist network, simulating empirical phenomena usually explained by current dual-process approaches of attitudes, thereby focusing on the processing mechanisms that may underlie both central and peripheral routes of persuasion. Major findings in attitude formation and change involving both processing modes are reviewed and modeled from a connectionist perspective. We use an autoassociative network architecture with a linear activation update and the delta learning algorithm for adjusting the connection weights. The network is applied to well-known experiments involving deliberative attitude formation, as well as the use of heuristics of length, consensus, expertise, and mood. All these empirical phenomena are successfully reproduced in the simulations. Moreover, the proposed model is shown to be consistent with algebraic models of attitude formation (Fishbein & Ajzen, 1975). The discussion centers on how the proposed network model may be used to unite and formalize current ideas and hypotheses on the processes underlying attitude acquisition and how it can be deployed to develop novel hypotheses in the attitude domain.
The Logic of Plausible Reasoning: A Core Theory
Authors: Collins Allan , Michalski Ryszard
Published: August 2005

The paper presents a core theory of human plausible reasoning based on analysis of people's answers to everyday questions about the world. The theory consists of three parts:

a formal representation of plausible inference patterns; such as deductions, inductions, and analogies, that are frequently employed in answering everyday questions;

a set of parameters, such as conditional likelihood, typicality, and similarity, that affect the certainty of people's answers to such questions; and

a system relating the different plausible inference patterns and the different certainty parameters.

This is one of the first attempts to construct a formal theory that addresses both the semantic and parametric aspects of the kind of everyday reasoning that pervades. all of human discourse.
Reinterpreting Visual Patterns in Mental Imagery
Authors: Finks Ronald A. , Pinker Steven , Farah Martha J.
Published: August 2005

In a recent paper, Chambers and Reisberg (1985) showed that people cannot reverse classical ambiguous figures in imagery (such as the Necker cube, duck/rabbit, or Schroeder staircase). In three experiments, we refute one kind of explanation for this difficulty: that visual images do not contain information about the geometry of a shape necessary for reinterpreting it or that people cannot apply shape classification procedures to the information in imagery. We show, that given suitable conditions, people can assign novel interpretations to ambiguous images which have been constructed out of parts or mentally transformed. For example, when asked to imagine the letter “D” on its side, affixed to the top of the letter “J”, subjects spontaneously report “seeing” an umbrella. We also show that these reinterpretations are not the result of guessing strategies, and that they speak directly to the issue of whether or not mental images of ambiguous figures can be reconstrued. Finally, we show that arguments from the philosophy literature on the relation between images and descriptions are not relevant to the issue of whether images can be reinterpreted, and we suggest possible explanations for why classical ambiguous figures do not spontaneously reverse in imagery.
Marker‐passing over Microfeatures: Towards a Hybrid Symbolic/Connectionist Model
Authors: Hendler James A.
Published: August 2005

Spreading activation, in the form of computer models and cognitive theories, has recently been undergoing a resurgence of interest in the cognitive science and AI communities. Two different types of cognitive models have been proposed to explain the activation spreading results. One approach, that of marker‐passing, concentrates on the spreading of symbolic information through an associative knowledge representation. The other technique, including the work in local connectionism, has focused on the passage of numeric information through a network. In this article, it is shown that these two techniques can be merged. The implementation of a mechanism in which a local‐connectionist‐like model is integrated with a symbolic marker‐passer is described and shows that the combined system is more powerful than either of the separate models alone. Finally, some early steps toward a hybrid model in which a distributed network is used to learn the microfeatures is described.
A Default‐Oriented Theory of Procedural Semantics
Authors: Hadley Robert F.
Published: August 2005

Procedural Semantics(PS), broadly construed, is the thesis that the meaning of a symbolic expression may be identified with procedures which specify how the expression is to be used, or applied to the world. J.A. Fodor has characterized PS as a wildly implausible form of the verification theory of meaning, and has argued that PS constitutes a plausible semantic theory only for highly simplistic universes, such as “blocks worlds” and databases. Fodor argued further that insofar as PS is defensible, it is “parasitic upon” classical denotational semantics. Fodor's critique of PS provoked various rejoinders. Although these rejoinders were not always in agreement, both Wilks and Woods reasoned that some form of PS must be true if we are to render coherent certain fundamental concepts of modeloretic semantics (e.g., denotations and truth‐conditions). In the present paper these arguments are reviewed and extended. It is argued that not only Tarskian semantics, but other forms of model‐theoretic semantics (including possible world and Situation Semantics) may very well ontologically presuppose some form of PS.

In addition, a default‐oriented form of PS is presented which avoids the “decision procedure” approach of early PS. The new theory embraces aspects of Quine's pragmatism, and assumes that semantic procedures may return pragmatic (default) truth values which may be revised, if the need arises, by adjudication procedures. On the theory here described, semantic procedures do not constitute the complete meanings of symbolic expressions, but constrain these meanings. It is argued that such constraints must exist if there are to be ontological foundations for such traditional notions as denotations and extensions.
Parallelism and Functionalism
Authors: Ramsey William M.
Published: August 2005

It has recently been argued by Paul Thagard (1986) that parallel computational models of cognition demonstrate the falsity of the popular theory of mind known as functionalism. It is my contention that his argument is seriously mistaken and rests on a misunderstanding of the functionalist position. While my primary aim is to defend functionalism from Thagard's attack, in the process I hope to provide some much needed clarification of matters both philosophical and computational. Since I intend to untangle issues that are often troublesome in cognitive science, the paper should prove useful even for those unfamiliar with Thagard's original piece.
Self‐Explanations: How Students Study and Use Examples in Learning to Solve Problems
Authors: Chi Michelene T.H. , Bassok Miriam , Lewis Matthew W. , Reimann Peter , Glaser Robert
Published: August 2005

The present paper analyzes the self‐generated explanations (from talk‐aloud protocols) that “Good” and “Poor” students produce while studying worked‐out examples of mechanics problems, and their subsequent reliance on examples during problem solving. We find that “Good” students learn with understanding: They generate many explanations which refine and expand the conditions for the action parts of the example solutions, and relate these actions to principles in the text. These self‐explanations are guided by accurate monitoring of their own understanding and misunderstanding. Such learning results in example‐independent knowledge and in a better understanding of the principles presented in the text. “Poor” students do not generate sufficient self‐explanations, monitor their learning inaccurately, and subsequently rely heavily on examples. We then discuss the role of self‐explanations in facilitating problem solving, as well as the adequacy of current AI models of explanation‐based learning to account for these psychological findings.
A Model of Competence for Counting
Authors: Smith Donald A. , Greeno James G. , Vitolo Theresa M.
Published: August 2005

A theoretical framework Is presented that distinguishes among three knowledge sources that form the basis for generative performance. The three knowledge sources, termed conceptual, procedural, and utilizational competence, were implemented as a computational model that derives plans for counting procedures. In a previous analysis, Greeno, Riley, and Gelman (1984) developed a characterization of the conceptual competence (implicit understanding of general concepts and principles) associated with the skill of counting and related conceptual competence to various models of performance. In the current work all three knowledge sources are formalized in a computer program (COUNTPLAN) that generates planning nets of counting procedures. The sufficiency of COUNTPLAN's knowledge components is demonstrated through its capacity to generate new plans for counting in novel settings from a core of conceptual competence. The utility of COUNTPLAN to facilitate the distinction between hypotheses of competence and hypotheses of performance is discussed.
Predicting Conversational Reports of a Personal Event
Authors: Tenney Yvette J.
Published: August 2005

This study concerns topic selection in conversational reports of a personal event, the birth of a baby. Ninety phone calls from 12 fathers and 7 mothers were analyzed in terms of the subject's prior concerns (prenatal questionnaire) and the outcome of events (postpartum questionnaire). Four analyses were conducted. The first showed that subjects were likely to mention topics of high, rather than low, prior concern, and unusual, rather than ordinary, outcome. The second showed that chronologically early topics were discussed before late topics. These findings were compatible with either a memory (i.e., “knowledge telling”) or a communication (i.e., “knowledge processing”) model of topic selection. Two additional analyses were conducted to evaluate predictions derived from each of these models. The first analysis showed that the conversations also contained a small set of pro forma topics that appeared earlier and more frequently than other topics. The second showed that these topics were more likely to be recipient‐initiated. These results suggest that reporters deviated from an optimal retrieval plan to take the recipient into account. The results as a whole support a communication‐based, “knowledge processing” (Bereiter & Scardomalia, 1980) model of topic selection.
Empirical Constraints on Computational Theories of Metaphor: Comments on Indurkhya
Authors: Gerrig Richard J.
Published: August 2005

Empirical analyses have provided some important constraints for computational theories of metaphor. Three such constraints relate to (1) the similar processing time for literal and metaphorical language, (2) the time‐limited processing of many metaphors, and (3) the dissociation of metaphor comprehension and appreciation. Indurkhya's (1986, 1987) model is discussed with respect to these issues.
Contributing to Discourse
Authors: Clark Herbert H. , Schaefer Edward F.
Published: August 2005

For people to contribute to discourse, they must do more than utter the right sentence at the right time. The basic requirement is that they add to their common ground in an orderly way. To do this, we argue, they try to establish for each utterance the mutual belief that the addressees have understood what the speaker meant well enough for current purposes. This is accomplished by the collective actions of the current contributor and his or her partners, and these result in units of conversation called contributions. We present a model of contributions and show how it accounts for a variety of features of everyday conversations.
Analogical Mapping by Constraint Satisfaction
Authors: Holyoak Keith J. , Thagard Paul
Published: August 2005

A theory of analogical mapping between source and target analogs based upon interacting structural, semantic, and pragmatic constraints is proposed here. The structural constraint of isomorphism encourages mappings that maximize the consistency of relational corresondences between the elements of the two analogs. The constraint of semantic similarity supports mapping hypotheses to the degree that mapped predicates have similar meanings. The constraint of pragmatic centrality favors mappings involving elements the analogist believes to be important in order to achieve the purpose for which the analogy is being used. The theory is implemented in a computer program called ACME (Analogical Constraint Mapping Engine), which represents constraints by means of a network of supporting and competing hypotheses regarding what elements to map. A cooperative algorithm for parallel constraint satisfaction identities mapping hypotheses that collectively represent the overall mapping that best fits the interacting constraints. ACME has been applied to a wide range of examples that include problem analogies, analogical arguments, explanatory analogies, story analogies, formal analogies, and metaphors. ACME is sensitive to semantic and pragmatic information if it is available, and yet able to compute mappings between formally isomorphic analogs without any similar or identical elements. The theory is able to account for empirical findings regarding the impact of consistency and similarity on human processing of analogies.
Inferring Causal History froms Shape
Authors: Leyton Michael
Published: August 2005

The shape of an object often seems to tell us something about the object's history; that is, the processes of growth, pushing, stretching, resistance, indentation, and so on, that formed the object. A theory is offered here of how people are able to infer the causal history of natural objects such as clouds, tumors, embryos, leaves, geological formations, and the like. Two inference problems are examined: the first is the inference of causal history from a single shape. It is claimed that this inference consists of two simple and yet powerful rules, based upon the symmetry and curvature structure of the shapes. When these two rules are applied to a large collection of shapes, it is found that the resulting causal histories accord remarkably well with intuition. The second inference problem is the recovery of intervening causal history between two successive shapes that are known to be two stages in the development of the same object. This type of inference is manifested, for example, when a doctor compares two X‐rays, taken a month apart, of the same tumor, and is able to conjecture the intervening growth. It is found that a grammar of only six operations is sufficient to generate the later shape from the earlier one via psychologically meaningful process‐extrapolations. Finally, a basic heuristic by which human beings seem to infer complex temporal relations between different processes in the past is proposed, and investigated in detail.
Schema Creation in Programming
Authors: Rist Robert S.
Published: August 2005

The creation of plan schemes is examined in a naturalistic, longitudinal study of problem solving. Ten novice programmers each wrote eight Pascal programs to solve a series of problems. Their protocols were analyzed to determine how declarative programming knowledge was used to create simple procedural program plans, and how the simple plans were used to create complex plans. Plan creation showed a process of backward development, from the goal to the plan focus, that port of the plan that directly implements the goal. Once defined; it is expanded to create the complete plan, showing backward development of plan parts from the focus. Once the plan is complete, it may be stored as a plan schema and retrieved in subsequent problem solving. The plan will then show forward development as it is implemented in schema order, the order in which plan pieces occur in the finished program. The change from backward development during creation to forward development after retrieval was strongly evident in the statistical analysis of the protocol data. Previous studies of novice programming, which showed only forward development, ore explained as special cases of this more general model, cases in which schema knowledge was available to the problem solver.
Non‐LIFO Execution of Cognitive Procedures
Authors: VanLehn Kurt , Ball William , Kowalski Bernadette
Published: August 2005

Many current theories of human problem solving and skill acquisition assume that people work only on the unsatisfied goal that was created most recently. That is, the architecture obeys a last‐in‐first‐out (LIFO) constraint on the selection of goals. This restriction seems necessary for the proper functioning of automatic learning mechanisms, such as production compilation and chunking. It is argued that this restriction is violated by some subjects on some tasks. In particular, 8 subjects (from a sample of 26) execute subtraction procedures in a way that violates the LIFO constraint. Although there is a great deal of between‐ and within‐subject strategy variation in the 8 subjects' behavior, it can be simply explained by hypothesizing that (1) the goal selection is not necessarily LIFO, (2) goal selection knowledge is represented by explicit preferences, and (3) the 8 subjects have just a few preferences that are overgeneralized, overspecialized, or missing. The rest of their preferences are correct. On the other hand, LIFO‐based models seem unable to explain the strategy variations in any simple way. Thus, it seems that part of the flexibility in human problem solving comes from having a choice of which goal to work on next. Fortunately, it is simple to ammend automatic learning mechanisms so that they will function correctly in a non‐LIFO architecture.
Rule acquisition events in the discovery of problem‐solving strategies
Authors: VanLehn Kurt
Published: August 2005

Although there are many machine‐learning programs that can acquire new problem‐solving strategies, it is not known exactly how their processes will manifest themselves in human behavior, if at all. In order to find out, a line‐by‐line protocol analysis was conducted of a subject discovering problem‐solving strategies. A model was developed that could explain 96% of the lines in the protocol. On this analysis, the subject's learning was confined to 11 rule acquisition events, wherein she temporarily abandoned her normal problem solving and focused on improving her strategic knowledge. Further analysis showed that: (1) Not all rule acquisition events are triggered by impasses; (2) Rules are acquired gradually, both because of competition between new and old rules, and because of the subject's apparently deliberate policy of gradual generalization. (3) This subject took a scientific approach to strategy discovery, even planning and conducting small experiments.
A computer model of the temporal course of agrammatic sentence understanding: The effects of variation in severity and sentence complexity
Authors: Haarmann Henk J. , Kolk Herman H.J.
Published: August 2005

In this article, we present SYNCHRON, a computer model of Kolk and van Grunsven's (1985) hypothesis of agrammatic comprehension deficits. According to this hypothesis, parsing fails in agrammatic aphasies since syntactic representational elements that need to be active simultaneously are often not coactive because of disturbances in timing due to brain damage. SYNCHRON has been especially designed to account for two neglected aspects of agrammatic comprehension: degrees of severity and the sentence‐complexity effect. We report an attempt to simulate data from two sentence‐picture‐matching studies in which a qualitatively similar sentence‐complexity effect was found at two different average levels of severity. This pattern was reproduced when the timing disorder was assumed to affect syntactic phrasal categories, but not when it was assumed to affect function‐word categories. When phrasal categories were involved, fit was not much affected, whether the damage was assumed to slow down the time for an element to be retrieved, or to decrease the time for an element to remain available.
Systematicity as a selection constraint in analogical mapping
Authors: Clement Catherine A. , Gentner Dedre
Published: August 2005

Analogy is often viewed as a partial similarity match between domains. But not all partial similarities qualify as analogy: There must be some selection of which commonalities count. Three experiments tested a particular selection constraint in analogical mapping, namely, systematicity. That is, we tested whether a given predicate is more likely to figure in the interpretation of and prediction from an analogy if the predicate participates in a common system of relations. In Experiment 1, subjects judged two matches to be included in an analogy: on isolated match, and a match embedded in a larger matching system. Subjects preferred the embedded match. In Experiments 2 and 3, subjects made analogical predictions about a target domain. Subjects predicted information that followed from a causal system that matched the base domain, rather than information that was equally plausible, but that created an isolated match with the base. Results support Gentner's (1983, 1989) structure‐mapping theory in that analogical mapping concerns systems and not individual predicates, and that attention to shared systematic structure constrains the selection of information to include in an analogy.
Belief ascription, metaphor, and intensional identification
Authors: Ballim Afzal , Wilks Yorick , Barnden John
Published: August 2005

This article discusses the extension of ViewGen, an algorithm derived for belief ascription, to the areas of intensional object identification and metaphor. ViewGen represents the beliefs of agents as explicit, partitioned proposition sets known as environments. Environments are convenient, even essential, for addressing important pragmatic issues of reasoning. The article concentrates on showing that the transfer of information in metaphors, intensional object identification, and ordinary, nonmetaphorical belief ascription can all be seen as different manifestations of a single environment‐amalgamation process. The article also briefly discusses the extension of ViewGen to speech‐act processing and the addition of a heuristic‐based, relevance‐determination procedure, and justifies the partitioning approach to belief ascription.
Why No Mere Mortal Has Ever Flown Out to Center Field
Authors: Kim John J. , Pinker Steven , Prince Alan , Prasada Sandeep
Published: August 2005

The English past tense system has recently been used to argue that formal grammatical categories (such as root, rule, and lexical item) may not be necessary to explain the acquisition and knowledge of language. Rumelhart and McClelland (1986) devised a connectionist model relying solely on phonological information; it is often suggested that any deficiencies of such a model can be remedied by supplying it with semantic information. These proposals are incorrect: Grammatical categories and abstract morphological structure are indispensable and cannot be replaced with semantics while preserving the patterns of psychological generalization in the system. Linguists have noted that irregular past tense mappings (e.g., fly/flew; stick/stuck) apply only when a verb's root is marked in the lexicon as having an irregular past. Because nouns are never so marked, verbs with noun roots—denominal verbs—are regular even if they are phonologically identical to irregular verbs, hence: flied out/*flew out to center field; high‐sticked/*high‐stuck the goalie. Experiment 1 shows that adult subjects are highly sensitive to this principle when rating regular and irregular past tense forms of novel versions of irregular sounding verbs: New verbs formed from nouns were judged as better with a regular past tense (e.g., line‐drived was the preferred past of “to hit a line drive”): new verbs formed from verbs were judged as better with an irregular past tense (e.g., line‐drive wsas the preferred past of “to drive along a line”). Experiment 2 replicated the results with noncollege‐educated adults, showing that the effect is not due to prescriptive language training. Experiment 3 tested an alternative to the formal grammatical account proposed by Lakoff (1987): When a verb has two meanings, one with an irregular past and one with a regular past, the irregular will belong to the meaning that is more central. Using regression techniques and ratings data, we disconfirm this prediction: In the data from Experiment 1, judgments of regular and irregular forms of a new verb are shown to be affected by whether the verb is derived from a noun or a verb, but not by whether its new sense is near the center or the periphery of the sense of the word it was derived from. Experiments 4 and 5 explain the few apparent counter‐examples by gathering independent evidence for a short‐circuiting process: When a denominal verb appears to have an irregular past tense form, it is because speakers sometimes interpret such verbs as having been derived directly from a related irregular verb root, bypassing the relevant noun. The experiments serve as a straightforward demonstration that representations of formal grammatical categories and structures are powerful determinants of linguistic behavior, and are not reducible to semantics, phonology, or prescriptive training.
Default Probability
Authors: Osherson Daniel N. , Stern Joshua , Wilkie Ormond , Stob Michael , Smith Edward E.
Published: August 2005

A probability may be called “default” if it is neither derived from preestablished probabilities nor based on considerations of frequency or symmetry. Default probabilities presumably arise through reasoning based on causality and similarity. This article advances a model of default probability based on a featural approach to similarity. The accuracy of the model is assessed by comparing its predictions to the probabilities provided by undergraduates asked to reason about mammals.