Verbal Models Research Articles

Mutation-order divergence by sexual selection: diversification of sexual signals in similar environments as a first step in speciation.

The origin of species remains a central question, and recent research focuses on the role of ecological differences in promoting speciation. Ecological differences create opportunities for divergent selection (i.e. 'ecological' speciation), a Darwinian hypothesis that hardly requires justification. In contrast, 'mutation-order' speciation proposes that, instead of adapting to different environments, populations find different ways to adapt to similar environments, implying that speciation does not require ecological differences. This distinction is critical as it provides an alternative hypothesis to the prevailing view that ecological differences drive speciation. Speciation by sexual selection lies at the centre of debates about the importance of ecological differences in promoting speciation; here, we present verbal and mathematical models of mutation-order divergence by sexual selection. We develop three general cases and provide a two-locus population genetic model for each. Results indicate that alternative secondary sexual traits can fix in populations that initially experience similar natural and sexual selection and that divergent traits and preferences can remain stable in the face of low gene flow. This stable divergence can facilitate subsequent divergence that completes or reinforces speciation. We argue that a mutation-order process could explain widespread diversity in secondary sexual traits among closely related, allopatric species.

The acquisition of discourse competence: Evidence from preschoolers' peer talk

In uncovering the mechanisms underlying language acquisition, developmental studies have tended to overlook the acquisitional relevance of child–child discourse. The purpose of this study is to explore the extent to which the acquisition of discourse competence with a special focus on metalanguage can be traced back to supportive interactional structures inherent in preschoolers' peer talk. Thus, a so far neglected acquisitional context is investigated with respect to a domain of language acquisition which is highly relevant for classroom participation and school success. Based on naturally occurring child–child interactions, the analyses examine how the participants establish, maintain, and direct ongoing discourse. The findings argue that peer talk has to be considered a rich acquisitional context offering children a platform to try out means of metalanguage that in adult–child interaction are often reserved for the adult. The results are discussed in relation to the question as to how children may benefit from verbal models supplied by adults but incorporated in and through specific interactional patterns of peer culture.

English

English

Strategies for improving the quality of verbal patient and family education: a review of the literature and creation of the EDUCATE model

Objective: Patient and family education includes print, audio-visual methods, demonstration, and verbal instruction. Our objective was to study verbal instruction as a component of patient and family education and make recommendations for best practices for healthcare providers who use this method. Methods: We conducted a literature review of articles from 1990 to 2014 about verbal education and collaborated on departmental presentations to determine best practices. A survey was sent to all nursing staff to determine perceptions of verbal education and barriers to learning. Results: Through our work, we were able to identify verbal education models, best practices, and needs. We then constructed the EDUCATE model of verbal education, which built upon our findings. Conclusion: Verbal education of patients and family members requires a multidisciplinary approach that takes into account learning styles, literacy, and culture to apply clear communication and methods for the assessment of learning. Providers need the skills, time, and training to effectively perform patient and family verbal education every time they care for patients. Further research needs to be performed on how to test, document, and quantify patients' comprehension and retention of verbal instructions.

Simulating the evolution of the human family: cooperative breeding increases in harsh environments.

Verbal and mathematical models that consider the costs and benefits of behavioral strategies have been useful in explaining animal behavior and are often used as the basis of evolutionary explanations of human behavior. In most cases, however, these models do not account for the effects that group structure and cultural traditions within a human population have on the costs and benefits of its members' decisions. Nor do they consider the likelihood that cultural as well as genetic traits will be subject to natural selection. In this paper, we present an agent-based model that incorporates some key aspects of human social structure and life history. We investigate the evolution of a population under conditions of different environmental harshness and in which selection can occur at the level of the group as well as the level of the individual. We focus on the evolution of a socially learned characteristic related to individuals' willingness to contribute to raising the offspring of others within their family group. We find that environmental harshness increases the frequency of individuals who make such contributions. However, under the conditions we stipulate, we also find that environmental variability can allow groups to survive with lower frequencies of helpers. The model presented here is inevitably a simplified representation of a human population, but it provides a basis for future modeling work toward evolutionary explanations of human behavior that consider the influence of both genetic and cultural transmission of behavior.

About the psycholinguistic models of the writing process for a didactics of written production1

This article problematises the possible areas of cooperation between psycholinguists and specialists in didactics by underlining both the interests of an interaction between them and the specific and complementary mission of both fields.After a historic overview of how references to psycholinguistic works emerged in the research on the didactics of written production, the main models of verbal production, especially of written verbal production, published during the 1980s and1990s are presented: Hayes and Flowers (1980), Garret (1980), Levelt (1989), Van Galen (1991). Their interest and the limits of their use in didactics are investigated. What is the possible function of verbal production models in didactics? What methodological precautions are necessary before using them? More particularly, the aids to writing possibly inspired by these models and the limits of such aids are examined. In a fourth part, we compare the ways in which each of the two disciplines approaches the key issue of learning.As a conclusion, the comparison of the methods respectively used in each of these fields, especially the part reserved to text analysis and real-time processes is useful to define an interesting cooperation area between psycholinguists, linguists and specialists in didactics, especially towards designing writing tasks and evaluation indicators.

How Does Climate Influence Speciation?

Variation in climatic conditions over space and time is thought to be an important driver of speciation. However, the role of climate has not been explored in the theoretical literature on speciation, and the theory underlying empirical studies of climate and speciation has come largely from informal, verbal models. In this study, we develop a quantitative model to test a relatively new but theoretically untested model of speciation (speciation via niche conservatism) and to examine the climatic conditions under which speciation via niche conservatism and speciation via niche divergence are most plausible. Our results have three broad implications for the study of speciation: (1) ecological similarity over time (niche conservatism) can be an important part of speciation, despite the traditional emphasis on ecological divergence, (2) long-term directional climate change promotes speciation via niche conservatism for species with low climatic-niche lability, whereas climatic oscillations promote speciation via niche divergence for species with high climatic-niche lability, and (3) population extinction can be a key component of speciation.

Computational modeling of bilingualism: How can models tell us more about the bilingual mind?

Models are no new beasts to scholars of bilingualism. During the last several decades we have seen many interesting and important models that postulate how the bilingual mind works. But specific, computationally implemented, models are far less common than general, verbal, models of bilingualism. This is because the former require efforts on the part of the researcher to conduct algorithmic and representational implementations, whereas the latter do not. The central question is: What good does implementation do in telling us about the bilingual mind beyond what the verbal models do? This Special Issue is an attempt to address this question with seven computational models of bilingualism from different research labs.

The genomic consequences of adaptive divergence and reproductive isolation between species of manakins

The processes of adaptation and speciation are expected to shape genomic variation within and between diverging species. Here we analyze genomic heterogeneity of genetic differentiation and introgression in a hybrid zone between two bird species (Manacus candei and M. vitellinus) using 59100 SNPs, a whole genome assembly, and Bayesian models. Measures of genetic differentiation (FST) and introgression (genomic cline center [α] and rate [β]) were highly heterogeneous among loci. We identified thousands of loci with elevated parameter estimates, some of which are likely to be associated with variation in fitness in Manacus populations. To analyze the genomic organization of differentiation and introgression, we mapped SNPs onto a draft assembly of the M. vitellinus genome. Estimates of FST, α, and β were autocorrelated at very short physical distances (<100 bp), but much less so beyond this. In addition, average statistical associations (linkage disequilibrium) between SNPs were generally low and were not higher in admixed populations than in populations of the parental species. Although they did not occur with a constant probability across the genome, loci with elevated FST, α, and β were not strongly co-localized in the genome. Contrary to verbal models that predict clustering of loci involved in adaptation and isolation in discrete genomic regions, these results are consistent with the hypothesis that genetic regions involved in adaptive divergence and reproductive isolation are scattered throughout the genome. We also found that many loci were characterized by both exceptional genetic differentiation and introgression, consistent with the hypothesis that loci involved in isolation are also often characterized by a history of divergent selection. However, the concordance between isolation and differentiation was only partial, indicating a complex architecture and history of loci involved in isolation.

Effects of a Naturalistic Sign Intervention on Expressive Language of Toddlers With Down Syndrome

In this study, the authors evaluated the effects of Enhanced Milieu Teaching (EMT; Hancock & Kaiser, 2006) blended with Joint Attention, Symbolic Play, and Emotional Regulation (JASPER; Kasari, Freeman, & Paparella, 2006) to teach spoken words and manual signs (Words + Signs) to young children with Down syndrome (DS). Four toddlers (ages 23-29 months) with DS were enrolled in a study with a multiple-baseline, across-participants design. Following baseline, 20 play-based treatment sessions (20-30 min each) occurred twice weekly. Spoken words and manual signs were modeled and prompted by a therapist who used EMT/JASPER teaching strategies. The authors assessed generalization to interactions with parents at home. There was a functional relation between the therapist's implementation of EMT/JASPER Words + Signs and all 4 children's use of signs during the intervention. Gradual increases in children's use of spoken words occurred, but there was not a clear functional relation. All children generalized their use of signs to their parents at home. The infusion of manual signs with verbal models within a framework of play, joint attention, and naturalistic language teaching appears to facilitate development of expressive sign and word communication in young children with DS.

Communication Takes Two

Communication Takes Two

Quantitative Variation in Autocrine Signaling and Pathway Crosstalk in the Caenorhabditis Vulval Network

Biological networks experience quantitative change in response to environmental and evolutionary variation. Computational modeling allows exploration of network parameter space corresponding to such variations. The intercellular signaling network underlying Caenorhabditis vulval development specifies three fates in a row of six precursor cells, yielding a quasi-invariant 3°3°2°1°2°3° cell fate pattern. Two seemingly conflicting verbal models of vulval precursor cell fate specification have been proposed: sequential induction by the EGF-MAP kinase and Notch pathways, or morphogen-based induction by the former. To study the mechanistic and evolutionary system properties of this network, we combine experimental studies with computational modeling, using a model that keeps the network architecture constant but varies parameters. We first show that the Delta autocrine loop can play an essential role in 2° fate specification. With this autocrine loop, the same network topology can be quantitatively tuned to use in the six-cell-row morphogen-based or sequential patterning mechanisms, which may act singly, cooperatively, or redundantly. Moreover, different quantitative tunings of this same network can explain vulval patterning observed experimentally in C. elegans, C. briggsae, C. remanei, and C. brenneri. We experimentally validate model predictions, such as interspecific differences in isolated vulval precursor cell behavior and in spatial regulation of Notch activity. Our study illustrates how quantitative variation in the same network comprises developmental patterning modes that were previously considered qualitatively distinct and also accounts for evolution among closely related species.

The Resolution of Sexual Antagonism by Gene Duplication

Disruptive selection between males and females can generate sexual antagonism, where alleles improving fitness in one sex reduce fitness in the other. This type of genetic conflict arises because males and females carry nearly identical sets of genes: opposing selection, followed by genetic mixing during reproduction, generates a population genetic "tug-of-war" that constrains adaptation in either sex. Recent verbal models suggest that gene duplication and sex-specific cooption of paralogs might resolve sexual antagonism and facilitate evolutionary divergence between the sexes. However, this intuitive proximal solution for sexual dimorphism potentially belies a complex interaction between mutation, genetic drift, and positive selection during duplicate fixation and sex-specific paralog differentiation. The interaction of these processes--within the explicit context of duplication and sexual antagonism--has yet to be formally described by population genetics theory. Here, we develop and analyze models of gene duplication and sex-specific differentiation between paralogs. We show that sexual antagonism can favor the fixation and maintenance of gene duplicates, eventually leading to the evolution of sexually dimorphic genetic architectures for male and female traits. The timescale for these evolutionary transitions is sensitive to a suite of genetic and demographic variables, including allelic dominance, recombination, sex linkage, and population size. Interestingly, we find that female-beneficial duplicates preferentially accumulate on the X chromosome, whereas male-beneficial duplicates are biased toward autosomes, independent of the dominance parameters of sexually antagonistic alleles. Although this result differs from previous models of sexual antagonism, it is consistent with several findings from the empirical genomics literature.

Inferring Biological Mechanisms by Data-Based Mathematical Modelling: Compartment-Specific Gene Activation during Sporulation in Bacillus subtilis as a Test Case.

Biological functionality arises from the complex interactions of simple components. Emerging behaviour is difficult to recognize with verbal models alone, and mathematical approaches are important. Even few interacting components can give rise to a wide range of different responses, that is, sustained, transient, oscillatory, switch-like responses, depending on the values of the model parameters. A quantitative comparison of model predictions and experiments is therefore important to distinguish between competing hypotheses and to judge whether a certain regulatory behaviour is at all possible and plausible given the observed type and strengths of interactions and the speed of reactions. Here I will review a detailed model for the transcription factor σ F, a regulator of cell differentiation during sporulation in Bacillus subtilis. I will focus in particular on the type of conclusions that can be drawn from detailed, carefully validated models of biological signaling networks. For most systems, such detailed experimental information is currently not available, but accumulating biochemical data through technical advances are likely to enable the detailed modelling of an increasing number of pathways. A major challenge will be the linking of such detailed models and their integration into a multiscale framework to enable their analysis in a larger biological context.

Analysis of verbal models in economics

The problems of evaluating verbal models in economics are discussed in terms of their testing for plagiarism, artificially generated texts, etc. It is noted that the scientific community is primarily interested in the adequate evaluation of verbal models, including books, theses, and scientific reports.

Acclimation of thermal physiology in natural populations ofDrosophila melanogaster : a test of an optimality model

Many organisms modify their physiological functions by acclimating to changes in their environment. Recent studies of thermal physiology have been influenced by verbal models that fail to consider the selective advantage of acclimation and thus make no predictions about variation in acclimation capacity. We used a quantitative model of optimal plasticity to generate predictions about the capacity of Drosophila melanogaster to acclimate to developmental temperature. This model predicts that the ability to acclimate thermal sensitivity should evolve when temperature varies greatly among generations. Based on the model, we expected that flies from the highly seasonal environment of New Jersey would acclimate thermal sensitivity more than would flies from the less seasonal environment of Florida. When raised at constant and fluctuating temperatures, flies from these populations failed to adjust their thermal optima in the way predicted by the model, suggesting that current assumptions about functional and genetic constraints should be reconsidered.

A Review of Red Queen Models for the Persistence of Obligate Sexual Reproduction

I present a historical review of coevolutionary models for the evolutionary persistence of sexual reproduction. The focus is on the fate of obligately sexual populations facing competition with one or more obligately asexual clones. An early simulation model by Hamilton (Hamilton WD. 1980. Sex versus non-sex versus parasite. Oikos. 35:282-290.) suggested that parasites could be an important force in selecting against asexual clones, leading to the persistence of sex. This result was consistent with a number of independent verbal models generated from 1975-1983. Conversely, the models by May and Anderson (May RM, Anderson RM. 1983. Epidemiology and genetics in the coevolution of parasites and hosts. Proc R Soc Lond B Biol Sci. 219:281-313.), which included more epidemiological detail, suggested that parasites were an unlikely source of selection to favor sexual over asexual reproduction. Thus began an oscillation of opinion regarding the role of parasites in selection for sex. It would seem at present that some of the differences of opinion over time stemmed from the different ways that models were constructed, including whether the sexual population was in competition with a genetically diverse asexual population or a single clonal genotype. On theoretical grounds, parasite-mediated selection for sex seems more likely if the sexual population has options in genotypic space that are not available to the clones. Models that incorporate more ecological realism also seem more favorable to the parasite theory of sex.

Antecedent stimulus control: Using orienting cues to facilitate first-word acquisition for nonresponders with autism

Although considerable progress has been made in improving the acquisition of expressive verbal communication in children with autism, research has documented that a subpopulation of children still fail to acquire speech even with intensive intervention. One variable that might be important in facilitating responding for this nonverbal subgroup of children is the use of antecedent orienting cues. Using a multiple baseline design, this study examined whether individualized orienting cues could be identified, and whether their presentation would result in the production of verbal expressive words. The results showed that this antecedent stimulus control procedure produced improvements in responding to verbal models in all of the children, and subsequent gains in speech for some of the children. Theoretical and applied implications of orienting cues as they relate to antecedent stimulus control for children with autism are discussed.

L’économique de l’habitation : une revue de lalittérature

This article has a two-fold purpose: first, to offer as complete an inventory aspossible of the literature written on the economics of housing, classifying thisliterature according to subject matter (in this sense, the article takes on theappearance of an annotated bibliography); and second, to take a hard look at thepresent state of economic theory in this field. The article is divided into the following six sections: 1) existing surveys;2) studies related to long-term cycles in residential construction; 3) theoriesexplaining short-term fluctuations; 4) verbal models; 5) econometric models;6) other studies. Some emphasis has been given to the authors' two principal conclusions. In theiropinion, the "residual" vision and the countercyclical hypothesis have not beenadequately tested in the past. Furthermore, the authors bring to light evidence,both theoretical and factual, which contradicts this theory (see Section 3). Then,in Section 5, the authors attempt to show how econometric models, except in the mostrecent papers, fail to take into account, adequately, the relationships between thehousing and mortgage markets and the builders. In addition, it is contended thatthese models are not truly representational of the whole sector, in that they areoften nothing more than simple demand or supply equations, or, even worse, neitherone nor the other.

Pollination Fluctuations Drive Evolutionary Syndromes Linking Dispersal and Mating System

The existence of a syndrome linking dispersal rate and mating system has long been debated in evolutionary ecology, especially in plants. Some verbal models hypothesize that the ability to self-fertilize may be associated with high dispersal, since completely outcrossing species cannot reproduce when they disperse to an empty destination site. However, empirical observations fail to support a clear trend, and an association of high colonizing ability with high outcrossing has been reported. Here we develop a general metapopulation model for the joint evolution of seed dispersal and self-fertilization when local pollen limitation varies stochastically over time. Under these assumptions, we study how dispersal and mating system influence each other through selection. We predict the existence of two consistent syndromes of traits: dispersing outcrossers and nondispersing (partial) selfers. These theoretical expectations contradict the classical view and shed new light on an old problem, allowing us to reinterpret empirical data. Finally, our predictions are discussed in light of empirical data concerning the association of seed dispersal mechanism and breeding system.