Object Assignment in S.C. Dik’s Functional Grammar: Marginal Accessibility in English

The approach to Subject and Object assignment in Dik ’s Functional Grammar is one of the most controversial aspects of the theory. Dik (1997) formulates a universal hierarchy of semantic functions determining accessibility to the Subject and Object functions. The “cut-off point ” for Object assignment in English is established after the Beneficiary. However, it is my contention that Object assignment is not restricted to Goal, Recipient and Beneficiary terms. As I will try to illustrate in this paper, there are other more marginal possibilities that suggest that the productivity of Object assigment is a matter of degree (cf. Brdar and Brdar Szabó 1993). La asignación de las funciones sintácticas Sujeto y Objeto es uno de los aspectos más problemáticos planteados en la Gramática Funcional de Dik (1997). En esta teoría las posibilidades de asignación de ambas funciones están determinadas por una jerarquía universal que ordena las funciones semánticas según su centralidad respecto a la predicación. El .“punto de interrupción.” para la asignación de la función Objeto en inglés se establece después de la función semántica Beneficiario. Sin embargo, aparte de las funciones Meta, Receptor y Beneficiario, existen otros candidatos menos prototípicos que pueden funcionar como Objeto en esta lengua, ya que, como intentaré demostrar en este trabajo, la asignación de esta función es una cuestión de grado (cfr. Brdar y Brdar Szabó 1993)

Typology of States of Affairs and semantic function assignment in the theory of Functional Grammar: critical approaches.

This paper is concerned with one specific area of S.C. Dik’s theory of Functional Grammar (FG) which has received a great deal of attention within the FG movement: the classification of States of Affairs and semantic functions. I will first focus on Dik’s (1978, 1989, 1997) proposals for a typology of SoAs, then presenting other alternative approaches by authors such as Rijksbaron (1989) and Goossens (1990), who suggested some interesting refinements of the 1978 and 1989 versions. Finally, the assignment of semantic and syntactic functions in FG will be briefly discussed, including some more recent advances and critical evaluations of Dik’s work. Este trabajo pretende profundizar en un área de la teoría de la Gramática Funcional (GF) de S.C. Dik que ha recibido especial atención dentro del modelo: la clasificación de los estados de cosas y la asignación de funciones semánticas. En primer lugar, se analizan las propuestas de Dik (1978, 1989, 1997) presentándose a continuación las aportaciones de otros autores, como Rijksbaron (1989) y Goossens (1990), que introdujeron interesantes modificaciones respecto a las versiones de 1978 y 1989. Finalmente, se abordará brevemente el tema de la asignación de funciones semánticas y sintácticas en la GF, incluyendo algunas de las aportaciones y valoraciones críticas más recientes

Intrinsic noise profoundly alters the dynamics and steady state of morphogen-controlled bistable genetic switches

During tissue development, patterns of gene expression determine the spatial arrangement of cell types. In many cases, gradients of secreted signaling molecules - morphogens - guide this process. The continuous positional information provided by the gradient is converted into discrete cell types by the downstream transcriptional network that responds to the morphogen. A mechanism commonly used to implement a sharp transition between two adjacent cell fates is the genetic toggle switch, composed of cross-repressing transcriptional determinants. Previous analyses emphasize the steady state output of these mechanisms. Here, we explore the dynamics of the toggle switch and use exact numerical simulations of the kinetic reactions, the Chemical Langevin Equation, and Minimum Action Path theory to establish a framework for studying the effect of gene expression noise on patterning time and boundary position. This provides insight into the time scale, gene expression trajectories and directionality of stochastic switching events between cell states. Taking gene expression noise into account predicts that the final boundary position of a morphogen-induced toggle switch, although robust to changes in the details of the noise, is distinct from that of the deterministic system. Moreover, stochastic switching introduces differences in patterning time along the morphogen gradient that result in a patterning wave propagating away from the morphogen source. The velocity of this wave is influenced by noise; the wave sharpens and slows as it advances and may never reach steady state in a biologically relevant time. This could explain experimentally observed dynamics of pattern formation. Together the analysis reveals the importance of dynamical transients for understanding morphogen-driven transcriptional networks and indicates that gene expression noise can qualitatively alter developmental patterning

Stochastic multi-scale models of competition within heterogeneous cellular populations: simulation methods and mean-field analysis

We propose a modelling framework to analyse the stochastic behaviour of heterogeneous, multi-scale cellular populations. We illustrate our methodology with a particular example in which we study a population with an oxygen-regulated proliferation rate. Our formulation is based on an age-dependent stochastic process. Cells within the population are characterised by their age. The age-dependent (oxygen-regulated) birth rate is given by a stochastic model of oxygen-dependent cell cycle progression. We then formulate an age-dependent birth-and-death process, which dictates the time evolution of the cell population. The population is under a feedback loop which controls its steady state size: cells consume oxygen which in turns fuels cell proliferation. We show that our stochastic model of cell cycle progression allows for heterogeneity within the cell population induced by stochastic effects. Such heterogeneous behaviour is reflected in variations in the proliferation rate. Within this set-up, we have established three main results. First, we have shown that the age to the G1/S transition, which essentially determines the birth rate, exhibits a remarkably simple scaling behaviour. This allows for a huge simplification of our numerical methodology. A further result is the observation that heterogeneous populations undergo an internal process of quasi-neutral competition. Finally, we investigated the effects of cell-cycle-phase dependent therapies (such as radiation therapy) on heterogeneous populations. In particular, we have studied the case in which the population contains a quiescent sub-population. Our mean-field analysis and numerical simulations confirm that, if the survival fraction of the therapy is too high, rescue of the quiescent population occurs. This gives rise to emergence of resistance to therapy since the rescued population is less sensitive to therapy

Mesoscopic and continuum modelling of angiogenesis

Angiogenesis is the formation of new blood vessels from pre-existing ones in response to chemical signals secreted by, for example, a wound or a tumour. In this paper, we propose a mesoscopic lattice-based model of angiogenesis, in which processes that include proliferation and cell movement are considered as stochastic events. By studying the dependence of the model on the lattice spacing and the number of cells involved, we are able to derive the deterministic continuum limit of our equations and compare it to similar existing models of angiogenesis. We further identify conditions under which the use of continuum models is justified, and others for which stochastic or discrete effects dominate. We also compare different stochastic models for the movement of endothelial tip cells which have the same macroscopic, deterministic behaviour, but lead to markedly different behaviour in terms of production of new vessel cells.Comment: 48 pages, 13 figure

Hybrid approaches for multiple-species stochastic reaction-diffusion models

Reaction-diffusion models are used to describe systems in fields as diverse as physics, chemistry, ecology and biology. The fundamental quantities in such models are individual entities such as atoms and molecules, bacteria, cells or animals, which move and/or react in a stochastic manner. If the number of entities is large, accounting for each individual is inefficient, and often partial differential equation (PDE) models are used in which the stochastic behaviour of individuals is replaced by a description of the averaged, or mean behaviour of the system. In some situations the number of individuals is large in certain regions and small in others. In such cases, a stochastic model may be inefficient in one region, and a PDE model inaccurate in another. To overcome this problem, we develop a scheme which couples a stochastic reaction-diffusion system in one part of the domain with its mean field analogue, i.e. a discretised PDE model, in the other part of the domain. The interface in between the two domains occupies exactly one lattice site and is chosen such that the mean field description is still accurate there. This way errors due to the flux between the domains are small. Our scheme can account for multiple dynamic interfaces separating multiple stochastic and deterministic domains, and the coupling between the domains conserves the total number of particles. The method preserves stochastic features such as extinction not observable in the mean field description, and is significantly faster to simulate on a computer than the pure stochastic model.Comment: 38 pages, 8 figure

Unidad didáctica : la publicidad

«La opción por un currículo abierto hace posible que cada centro adecúe la respuesta educativa a su contexto favoreciendo el contacto con la realidad y el partir de problemas reales y próximos con posibilidad de incidir en su transformación» (Álvarez y Jiménez, 1992). Las autoras de este artículo proponen una unidad didáctica para el tercer curso de ESO -adaptable a cualquier otro- que se fundamenta en los principios de la actual generalización de la Reforma educativa y en la necesidad de utilizar y analizar críticamente, los medios de comunicación, en este caso la publicidad.“The option of an open curricula makes it possible for each centre to adequate the educational answer to its context, favouring the contact with reality and starting with real and proximate problems with the possibility of influencing in their transformation” (Alvarez and Jiménez, 1992). The authors of this article propose a didactic unit for the third course of ESO –although adaptable to any other- which bases on the current generalization of the educational Reform and the necessity of using and analysing media critically, in this case referring to advertising

Minimum Action Path theory reveals the details of stochastic biochemical transitions out of oscillatory cellular states

Cell state determination is the outcome of intrinsically stochastic biochemical reactions. Tran- sitions between such states are studied as noise-driven escape problems in the chemical species space. Escape can occur via multiple possible multidimensional paths, with probabilities depending non-locally on the noise. Here we characterize the escape from an oscillatory biochemical state by minimizing the Freidlin-Wentzell action, deriving from it the stochastic spiral exit path from the limit cycle. We also use the minimized action to infer the escape time probability density function

Data graduation based on statistical time series methods

Whittaker's method is one of the most frequently employed techniques to graduate mortality tables. In order for the method to work and produce reasonable results, some subjective input is required from the graduator. In this paper we show that Whittaker' s solution to the graduation problem can be approached from a statistical time series model-based perspective that reduces the subjectivity in its application. It also serves to interpret the graduation problem as a classical estimation problem. In fact, on the basis of some suitable assumptions, we are able to show thatthe Best Linear Unbiased Estimator of the true mortality rates has the form of Whittaker's solution. We also provide some complementary analytical tools aimed at helping the graduator to employ the method in practice and interpret its results from a statistical standpoint. A numerical illustration is shown in detail to exemplify the application of our proposal

La comprensión lectora en ELE. Análisis de manuales de B1 con base en su tipología textual

Si la comprensión lectora es uno de los pilares esenciales para el aprendizaje de una lengua, el texto se convierte en su vehículo esencial. Además, aunque las tecnologías tienen cada vez mayor presencia en el aula, la realidad es que, a día de hoy, el manual sigue constituyendo un elemento esencial para el trabajo en la clase de idiomas. Por este motivo, en el siguiente trabajo se ha realizado un estudio y análisis exploratorio-cuantitativo-estadístico de las distintas tipologías textuales que aparecen en cuatro de los manuales de mayor difusión en la enseñanza de español para extranjeros, concretamente en el nivel B1: Meta ELE. Curso de español de supervivencia B1.1 (Edelsa, 2012), Nuevo español en marcha 3 (SGEL, 2014), Nuevo sueña 2 (Grupo Anaya, 2015) y Nuevo Prisma (Edinumen, 2015). Con este análisis se han obtenido nuevos datos sobre porcentajes, frecuencias y diversidad de las tipologías textuales que aparecen en ellos. De esta forma y, tras la interpretación de los resultados obtenidos, se ha podido comprobar si estos se adaptan o no al plan curricular establecido por el MCER o si existe una diversidad textual tal con la que el alumno pueda enfrentarse a todo tipo de textos en su aprendizaje, trabajando de este modo la comprensión lectora de una manera completa y global desde las distintas estructuras y recursos que cada tipología ofrece