Exemplar Model Research Articles

Context and paradigms

A small but growing body of research on English and Dutch has found that pronunciation of affixes in a word form is sensitive to paradigmatic probability – i.e., the probability of using that form over other words in the same morphological paradigm. Yet it remains unclear (a) how paradigmatic probability is best measured; (b) whether an increase in paradigmatic probability leads to phonetic enhancement or reduction; and (c) by what mechanism paradigmatic probability can affect pronunciation. The current work examines pronunciation variation of Russian verbal agreement suffixes. I show that there are two distinct patterns of variation, corresponding to two different measures of paradigmatic probability. One measure, pairwise paradigmatic probability, is associated with a pronunciation pattern that resembles phonetic enhancement. The second measure, lexeme paradigmatic probability, can show enhancement effects, but can also yield reduction effects more similar to those of contextual probability. I propose that these two patterns can be explained in an exemplar model of lexical storage. Reduction effects are the consequence of faster retrieval and encoding of an articulatory target, while effects that resemble enhancement result when the pronunciation target of both members of a pair of competing word forms is shifted towards the more frequent of two.

Speaker-specific processing and local context information: The case of speaking rate

ABSTRACTTo deal with variation in the speech signal, listeners rely on local context, such as speaking rate in a carrier sentence directly preceding a target, as well as more global properties of the speech signal, such as speaker-specific pronunciation variants. The present study addressed whether, despite its variability even within one speaker, habitual speaking rate can be tracked as a speaker-specific property and how such speaker-specific tracking of habitual rate would interact with effects of local-rate normalization. In two experiments, listeners were exposed to a 2-min dialogue between a fast and a slow speaker. At test, listeners categorized minimal word pair continua differing in the German /a/–/a:/ duration contrast spoken by the same two speakers. The results showed that listeners responded with /a:/ more often for the fast speaker but only when words were presented in isolation and not when presented with additional local-rate information. That is, despite the general assumption that duration cues and speaking rate are too variable to be used in a speaker-specific fashion, tracking habitual speaking rate may help speech perception. The results are discussed in relation to a belief-updating model of perceptual adaptation and exemplar models.

Prototypes, exemplars and the response scaling parameter: A Bayes factor perspective

The Bayes factor can be used to break the stalemate between prototype and exemplar theorists in category learning. Exemplar theorists do not accept prototype theorists’ results, because these results are often based on a restricted version of the exemplar model, without response scaling parameter. Prototype theorists do not accept exemplar theorists’ results, because these results are often based on comparing fits of models that are unbalanced in their number of parameters. Using the Bayes factor alleviates concerns about differences in model complexity between exemplar and prototype models, because it takes away the prototype theorists’ fear that their model is disadvantaged, and it eliminates the need to use a constrained version of the exemplar model exemplar theorists have abandoned. Further, by virtue of its sensitivity to the prior, the adoption of the Bayes factor encourages more complete theorizing about the relevant psychological processes instantiated in the models, and increases the empirical content of the models.

Feminist pedagogy as a new initiative in the education of South African teachers

Not much has been published about feminist pedagogy and teacher education in South Africa. The purpose of this article is to introduce the above to the South African education fraternity, where it has not yet found a comfortable home. The problem of the study focues on two issues: the lack of an alternative teacher education perspective and experience in South Africa, and the possibility of teacher education for the new gender order, and a revival of the gender equity debate. The purpose of the study is to reflect on the gendered (patriarchal) teacher education models, enhance the pre-service teachers' understanding of the power relations in education, and argue the case for the inclusion of feminist pedagogy in teacher education programmes. A qualitative conceptual document analysis was used as research design. The article is concluded with an exemplar teacher education model in which student teachers are introduced to a critical study of learning to teach (feminist pedagogy), and a feminist classroom setting. https://doi.org/10.19108/KOERS.80.4.2215

Aerobic Exercise for Reducing Migraine Burden: Mechanisms, Markers, and Models of Change Processes.

Engagement in regular exercise routinely is recommended as an intervention for managing and preventing migraine, and yet empirical support is far from definitive. We possess at best a weak understanding of how aerobic exercise and resulting change in aerobic capacity influence migraine, let alone the optimal parameters for exercise regimens as migraine therapy (eg, who will benefit, when to prescribe, optimal types, and doses/intensities of exercise, level of anticipated benefit). These fundamental knowledge gaps critically limit our capacity to deploy exercise as an intervention for migraine. Clear articulation of the markers and mechanisms through which aerobic exercise confers benefits for migraine would prove invaluable and could yield insights on migraine pathophysiology. Neurovascular and neuroinflammatory pathways, including an effect on obesity or adiposity, are obvious candidates for study given their role both in migraine as well as the changes known to accrue with regular exercise. In addition to these biological pathways, improvements in aerobic fitness and migraine alike also are mediated by changes in psychological and sociocognitive factors. Indeed a number of specific mechanisms and pathways likely are operational in the relationship between exercise and migraine improvement, and it remains to be established whether these pathways operate in parallel or synergistically. As heuristics that might conceptually benefit our research programs here forward, we: (1) provide an extensive listing of potential mechanisms and markers that could account for the effects of aerobic exercise on migraine and are worthy of empirical exploration and (2) present two exemplar conceptual models depicting pathways through which exercise may serve to reduce the burden of migraine. Should the promise of aerobic exercise as a feasible and effective migraine therapy be realized, this line of endeavor stands to benefit migraineurs (including the many who presently remain suboptimally treated) by providing a new therapeutic avenue as an alternative or augmentative compliment to established interventions for migraine.

Modeling Healthcare Processes Using Commitments: An Empirical Evaluation.

The two primary objectives of this paper are: (a) to demonstrate how Comma, a business modeling methodology based on commitments, can be applied in healthcare process modeling, and (b) to evaluate the effectiveness of such an approach in producing healthcare process models. We apply the Comma approach on a breast cancer diagnosis process adapted from an HHS committee report, and presents the results of an empirical study that compares Comma with a traditional approach based on the HL7 Messaging Standard (Traditional-HL7). Our empirical study involved 47 subjects, and two phases. In the first phase, we partitioned the subjects into two approximately equal groups. We gave each group the same requirements based on a process scenario for breast cancer diagnosis. Members of one group first applied Traditional-HL7 and then Comma whereas members of the second group first applied Comma and then Traditional-HL7—each on the above-mentioned requirements. Thus, each subject produced two models, each model being a set of UML Sequence Diagrams. In the second phase, we repartitioned the subjects into two groups with approximately equal distributions from both original groups. We developed exemplar Traditional-HL7 and Comma models; we gave one repartitioned group our Traditional-HL7 model and the other repartitioned group our Comma model. We provided the same changed set of requirements to all subjects and asked them to modify the provided exemplar model to satisfy the new requirements. We assessed solutions produced by subjects in both phases with respect to measures of flexibility, time, difficulty, objective quality, and subjective quality. Our study found that Comma is superior to Traditional-HL7 in flexibility and objective quality as validated via Student’s t-test to the 10% level of significance. Comma is a promising new approach for modeling healthcare processes. Further gains could be made through improved tooling and enhanced training of modeling personnel.

An exemplar-model account of feature inference from uncertain categorizations.

In a highly systematic literature, researchers have investigated the manner in which people make feature inferences in paradigms involving uncertain categorizations (e.g., Griffiths, Hayes, & Newell, 2012; Murphy & Ross, 1994, 2007, 2010a). Although researchers have discussed the implications of the results for models of categorization and inference, an explicit formal model that accounts for the full gamut of results has not been evaluated. Building on previous proposals, in this theoretical note I consider the predictions from an exemplar model of categorization in which the inferred category label becomes a new feature of the objects. The model predicts a priori a wide range of robust results that have been documented in this literature and can also be used to interpret effects of experimental manipulations (PsycINFO Database Record

Visceral obesity stimulates anaphase bridge formation and spindle assembly checkpoint dysregulation in radioresistant oesophageal adenocarcinoma.

Oesophageal adenocarcinoma is an exemplar model of obesity-associated cancer. Locally advanced disease is treated with neoadjuvant chemoradiotherapy, and survival rates are highest in patients demonstrating a pathological response following neoadjuvant therapy. Given that 55% of oesophageal adenocarcinoma patients are obese, uncovering the effect of adipose tissue on radioresponse is clinically relevant. This study investigates if adipose tissue activates genomic instability events in radioresponsive (OE33P) and radioresistant (OE33R) oesophageal cancer cell lines and tumour samples. OE33R and OE33P were cultured with adipose-conditioned media derived from oesophageal adenocarcinoma patients (n=10). Anaphase bridges, a marker of genomic instability, were enumerated in both cell lines following treatment with adipose media, and normalised to cell number. Genomic instability is regulated by the spindle assembly complex. Expression of two spindle assembly complex genes (MAD2L2, BUB1B) was assessed using qPCR, and validated in patient tumour specimens from viscerally obese (n=46) and nonobese patients (n=41). Adipose-conditioned media increased anaphase bridging in OE33R (p<0.0001), with a threefold increase in OE33R compared to OE33P (p<0.01). Levels of anaphase bridges in OE33R cells correlated with visceral obesity status as measured by waist circumference (R=0.709, p=0.03) and visceral fat area (R=0.794, p=0.006). Adipose tissue altered expression of MAD2L2 in vitro. In vivo, MAD2L2 expression was higher in viscerally obese oesophageal adenocarcinoma patients compared with nonobese patients (p<0.05). Anaphase bridge levels are influenced by obesity and radiosensitivity status in oesophageal adenocarcinoma. Furthermore, visceral adipose-conditioned media stimulates dysregulation of the spindle assembly complex in oesophageal adenocarcinoma patients.

One Giant Leap for Categorizers: One Small Step for Categorization Theory.

We explore humans’ rule-based category learning using analytic approaches that highlight their psychological transitions during learning. These approaches confirm that humans show qualitatively sudden psychological transitions during rule learning. These transitions contribute to the theoretical literature contrasting single vs. multiple category-learning systems, because they seem to reveal a distinctive learning process of explicit rule discovery. A complete psychology of categorization must describe this learning process, too. Yet extensive formal-modeling analyses confirm that a wide range of current (gradient-descent) models cannot reproduce these transitions, including influential rule-based models (e.g., COVIS) and exemplar models (e.g., ALCOVE). It is an important theoretical conclusion that existing models cannot explain humans’ rule-based category learning. The problem these models have is the incremental algorithm by which learning is simulated. Humans descend no gradient in rule-based tasks. Very different formal-modeling systems will be required to explain humans’ psychology in these tasks. An important next step will be to build a new generation of models that can do so.

Precarious or Purposeful? Proactively Building Inclusive Special Education Service Delivery on Solid Ground

AbstractThe absence of unified and inclusive special education service delivery models represents a longstanding challenge to the education of students with the full range of disabilities in inclusive schools and classrooms. An exemplar model is offered for elementary schools within a multi-tiered system of support (MTSS) framework. To establish its practicality and cost-neutrality, the development of the exemplar model was based on personnel utilization data from 69 schools. After building a case for the importance of proactively developing inclusive models of special education service delivery, this article describes: (a) the types and source of the data upon which the exemplar model is based, (b) a set of underlying assumptions, (c) school demographic parameters upon which the exemplar model is based, (d) a comparison of 13 key variables between their actual averages in sampled schools with their proposed status in the exemplar model, and (e) nine conceptual and programmatic shifts designed to accompany the structural changes presented in the exemplar model. The article concludes with implications for practice and future research. Overall, the exemplar model is offered as a starting point to spur discussion, creative problem solving, and action planning to explore model development suited to local contexts.

Generating structure from experience: A retrieval-based model of language processing.

Standard theories of language generally assume that some abstraction of linguistic input is necessary to create higher level representations of linguistic structures (e.g., a grammar). However, the importance of individual experiences with language has recently been emphasized by both usage-based theories (Tomasello, 2003) and grounded and situated theories (e.g., Zwaan & Madden, 2005). Following the usage-based approach, we present a formal exemplar model that stores instances of sentences across a natural language corpus, applying recent advances from models of semantic memory. In this model, an exemplar memory is used to generate expectations about the future structure of sentences, using a mechanism for prediction in language processing (Altmann & Mirković, 2009). The model successfully captures a broad range of behavioral effects-reduced relative clause processing (Reali & Christiansen, 2007), the role of contextual constraint (Rayner & Well, 1996), and event knowledge activation (Ferretti, Kutas, & McRae, 2007), among others. We further demonstrate how perceptual knowledge could be integrated into this exemplar-based framework, with the goal of grounding language processing in perception. Finally, we illustrate how an exemplar memory system could have been used in the cultural evolution of language. The model provides evidence that an impressive amount of language processing may be bottom-up in nature, built on the storage and retrieval of individual linguistic experiences.

An Eye-Tracking Study of Multiple Feature Value Category Structure Learning: The Role of Unique Features.

We examined whether the degree to which a feature is uniquely characteristic of a category can affect categorization above and beyond the typicality of the feature. We developed a multiple feature value category structure with different dimensions within which feature uniqueness and typicality could be manipulated independently. Using eye tracking, we found that the highest attentional weighting (operationalized as number of fixations, mean fixation time, and the first fixation of the trial) was given to a dimension that included a feature that was both unique and highly typical of the category. Dimensions that included features that were highly typical but not unique, or were unique but not highly typical, received less attention. A dimension with neither a unique nor a highly typical feature received least attention. On the basis of these results we hypothesized that subjects categorized via a rule learning procedure in which they performed an ordered evaluation of dimensions, beginning with unique and strongly typical dimensions, and in which earlier dimensions received higher weighting in the decision. This hypothesis accounted for performance on transfer stimuli better than simple implementations of two other common theories of category learning, exemplar models and prototype models, in which all dimensions were evaluated in parallel and received equal weighting.

Repetition-free longest common subsequence of random sequences

A repetition-free Longest Common Subsequence (LCS) of two sequences x and y is an LCS of x and y where each symbol may appear at most once. Let R denote the length of a repetition-free LCS of two sequences of n symbols each one chosen randomly, uniformly, and independently over a k-ary alphabet. We study the asymptotic, in n and k, behavior of R and establish that there are three distinct regimes, depending on the relative speed of growth of n and k. For each regime we establish the limiting behavior of R. In fact, we do more, since we actually establish tail bounds for large deviations of R from its limiting behavior.Our study is motivated by the so called exemplar model proposed by Sankoff (1999) and the related similarity measure introduced by Adi et al. (2010). A natural question that arises in this context, which as we show is related to long standing open problems in the area of probabilistic combinatorics, is to understand the asymptotic, in n and k, behavior of parameter R.

High-Quality Depth Estimation Using an Exemplar 3D Model for Stereo Conversion.

High-quality depth painting for each object in a scene is a challenging task in 2D to 3D stereo conversion. One way to accurately estimate the varying depth within the object in an image is to utilize existing 3D models. Automatic pose estimation approaches based on 2D-3D feature correspondences have been proposed to obtain depth from a given 3D model. However, when the 3D model is not identical to the target object, previous methods often produce erroneous depth in the vicinity of the silhouette of the object. This paper introduces a novel 3D model-based depth estimation method that effectively produces high-quality depth information for rigid objects in a stereo conversion workflow. Given an exemplar 3D model and user correspondences, our method generates detailed depth of an object by optimizing the initial depth obtained by the application of structural fitting and silhouette matching in the image domain. The final depth is accurate up to the given 3D model, while consistent with the image. Our method was applied to various image sequences containing objects with different appearances and varying poses. The experiments show that our method can generate plausible depth information that can be utilized for high-quality 2D to 3D stereo conversion.

Schema Theory as a Construction Grammar

Construction grammar, recently described as “the fastest growing linguistic and interdisciplinary approach to language” (Goldberg 2013, 30) has its foundations in the psychology of human categorization and other general cognitive abilities. So does schema theory in music. In the first extended comparison of these research programs, we present six central principles of construction grammar and demonstrate their relevance and applicability to schema-theoretic studies of music: 1) grammatical constructions, 2) surface structure, 3) a network of constructions, 4) cross-linguistic variability and generalization, 5) usage-based knowledge, and 6) exemplar models. Because studies in child development have played such an important role in changing how scholars view language acquisition and grammar formation (Tomasello 2003) we have chosen to illustrate many of the arguments with musical examples drawn from eighteenth- and nineteenth-century conservatories. An orphan at one of the eighteenth-century conservatories in Naples, the prodigy Henri Fissot at the Paris Conservatory in the 1850s, and the young Rachmaninoff at the Moscow Conservatory in the 1890s all learned the art of composition through the age-old practice of child apprenticeship. From the musical utterances made by these apprentices in response to exercises and contests one can infer much about the grammar being acquired. Extensive musical examples suggest that construction grammar can provide a model for how a large repertory of learned patterns of varying dimensions can collectively function as a flexible and adaptive music grammar.

Fine-grained and probabilistic cross-linguistic influence in the pronunciation of cognates: Evidence from corpus-based spontaneous conversation and experimentally elicited data

AbstractThe present study examines variable realizations of Spanish word-initial voiced and voiceless dental stops in Spanish-English cognate pairs. Employing a variationist approach to naturalistic data, we report significantly decreased likelihood of reduced articulations of word-initial /d/ in cognates in spontaneous bilingual Puerto Rican discourse, and no such probabilistic effect for cognates in monolingual Spanish of the same speech community. Using experimentally controlled elicited data of Spanish word-initial /t/, we also find evidence of significant fine-grained effects of English on the articulations of Spanish cognates in the form of lengthened VOT for Spanish-English bilinguals. These results indicate that cross-language lexical connections affect phonetic categories in the speech production of Spanish-English bilinguals. It is proposed that both fine-grained and probabilistic effects of the phonology of one language on another can be explained within the Exemplar Model of Lexical Representation.

The Influence of Word Retrieval and Planning on Phonetic Variation: Implications for Exemplar Models.

Over the past several decades, an increasing number of empirical studies have documented the interaction of information across the traditional linguistic modules of phonetics, phonology, and lexicon. For example, the frequency with which a word occurs influences its phonetic properties of its sounds; high frequency words tend to be reduced relative to low frequency words. Lexicalist Exemplar Models have been successful in accounting for this body of results through a single mechanism, exemplars- memory representations that integrate lexical, phonological, and phonetic information into a single structure. We review recent studies that suggest there are critical limitations to assuming that phonetic variation solely reflects the storage of word labels and sound structure in exemplars. Specifically, these studies show that factors related to the on-line retrieval and planning of lexical items also influence phonetic variation. The implications of these findings for exemplar models are discussed; the relationship of exemplar storage to the broader cognitive system is examined, as well as alternative theoretical frameworks incorporating gradience at all levels of linguistic representation.

Liderazgo en medicina: ¿debemos enseñarlo y evaluarlo?

IntroductionThe teaching and practice of the health sciences has become an ever more complex task, saturated with challenges that require leadership skills and organizational change. In the last 20 or 30 years, the academic productivity on leadership has had a veritable explosion. Teachers and learners involved in human resources training in health need to be aware of this information, in order to use it in their practice and personal development. ObjectiveTo provide a current overview of leadership in medicine and its educational implications. MethodNarrative review of the literature. The following themes were analyzed: relevance of leadership in the teaching and practice of medicine; definition of leadership; leadership as trait vs. process; assigned vs. emergent leadership; leadership vs. management; teaching leadership in the medical education continuum; reflections about its learning and assessment. DiscussionThe appropriate application of the modern concepts of leadership can be a determining factor of the educational and clinical outcomes in hospitals and universities. There is a vast amount of academic literature on the topic that can inform clinicians and healthcare teachers, as well as an enormous availability of online and face-to-face educational activities on leadership in healthcare and education. Two exemplar models of the application of the leadership concept in medical education have taken place in Canada and the United Kingdom. The majority of original research papers on leadership in medicine and medical education have been published in North America, thus there is a need for original studies and curricular development on healthcare leadership in a local and national context, without losing the global perspective. ConclusionCompetencies in effective leadership should be considered during educational planning in healthcare professions schools and health sciences institutions.

The role of social information in cognitive processing: Sex and sexuality

Exemplar models of cognitive linguistic processing hold that humans' robust memory faculty allows for the construction of “exemplars” or prototypes gained through statistical procedures applied to experiential memories of variation (Pierrehumbert, 2006). Since they are based upon experiential memories, exemplar clouds are sensitive to social information. As Mendoza-Denton et al. (2003) note, congruence between the variant and the center of the exemplar cloud often facilitates cognitive processing. Both speaker age (Walker and Hay, 2011) and speaker sex (Sumner and King, 2013) have been shown to affect semantic processing. Expanding upon these investigations, the current study examines a new social variable, sexuality. First, a lexical association task was carried out to construct a corpus of word-pairs whose semantic links differed for straight female, male, and gay male speakers. Then, the effect of congruence between speaker sexuality, gender, and semantic pair was investigated in a lexical decision tas...

A geospatial framework to support integrated biogeochemical modelling in the United Kingdom

Anthropogenic impacts on the aquatic environment, especially in the context of nutrients, provide a major challenge for water resource management. The heterogeneous nature of policy relevant management units (e.g. catchments), in terms of environmental controls on nutrient source and transport, leads to the need for holistic management. However, current strategies are limited by current understanding and knowledge that is transferable between spatial scales and landscape typologies. This study presents a spatially-explicit framework to support the modelling of nutrients from land to water, encompassing environmental and spatial complexities. The framework recognises nine homogeneous landscape units, distinct in terms of sensitivity of nutrient losses to waterbodies. The functionality of the framework is demonstrated by supporting an exemplar nutrient model, applied within the Environmental Virtual Observatory pilot (EVOp) cloud cyber-infrastructure. We demonstrate scope for the use of the framework as a management decision support tool and for further development of integrated biogeochemical modelling.