Early development and predictors of morphological awareness: disentangling the impact of decoding skills and phonological awareness

Background: Morphological Awareness (MA) has been demonstrated to be influential on the reading outcomes of children and adults. Yet, little is known regarding MA's early development. Aim: The aim of this study is to better understand MA at different stages of development and its association with Phonological Awareness (PA) and reading. Methods and procedures: In a longitudinal design the development of MA was explored in a group of pre-reading children with a family risk of dyslexia and age-matched controls from kindergarten up to and including grade 2. Outcomes and results: MA deficits were observed in the group with literacy difficulties at all time points. PA was only found to make a significant contribution to MA development at the early stages of formal reading instruction. While first-grade decoding skills were found to contribute significantly to MA in second grade. Conclusions: Evidence supporting a bidirectional relation was found and supports the need for adequate MA intervention and explicit instruction for “at risk” children in the early stages of literacy instruction

Predicting future reading problems based on pre-reading auditory measures: a longitudinal study of children with a familial risk of dyslexia

Purpose: This longitudinal study examines measures of temporal auditory processing in pre-reading children with a family risk of dyslexia. Specifically, it attempts to ascertain whether pre-reading auditory processing, speech perception, and phonological awareness (PA) reliably predict later literacy achievement. Additionally, this study retrospectively examines the presence of pre-reading auditory processing, speech perception, and PA impairments in children later found to be literacy impaired. Method: Forty-four pre-reading children with and without a family risk of dyslexia were assessed at three time points (kindergarten, first, and second grade). Auditory processing measures of rise time (RT) discrimination and frequency modulation (FM) along with speech perception, PA, and various literacy tasks were assessed. Results: Kindergarten RT uniquely contributed to growth in literacy in grades one and two, even after controlling for letter knowledge and PA. Highly significant concurrent and predictive correlations were observed with kindergarten RT significantly predicting first grade PA. Retrospective analysis demonstrated atypical performance in RT and PA at all three time points in children who later developed literacy impairments. Conclusions: Although significant, kindergarten auditory processing contributions to later literacy growth lack the power to be considered as a single-cause predictor; thus results support temporal processing deficits’ contribution within a multiple deficit model of dyslexia

Variation in habitat choice and delayed reproduction: Adaptive queuing strategies or individual quality differences?

In most species, some individuals delay reproduction or occupy inferior breeding positions. The queue hypothesis tries to explain both patterns by proposing that individuals strategically delay breeding (queue) to acquire better breeding or social positions. In 1995, Ens, Weissing, and Drent addressed evolutionarily stable queuing strategies in situations with habitat heterogeneity. However, their model did not consider the non - mutually exclusive individual quality hypothesis, which suggests that some individuals delay breeding or occupy inferior breeding positions because they are poor competitors. Here we extend their model with individual differences in competitive abilities, which are probably plentiful in nature. We show that including even the smallest competitive asymmetries will result in individuals using queuing strategies completely different from those in models that assume equal competitors. Subsequently, we investigate how well our models can explain settleme! nt patterns in the wild, using a long-term study on oystercatchers. This long-lived shorebird exhibits strong variation in age of first reproduction and territory quality. We show that only models that include competitive asymmetries can explain why oystercatchers' settlement patterns depend on natal origin. We conclude that predictions from queuing models are very sensitive to assumptions about competitive asymmetries, while detecting such differences in the wild is often problematic.

Full- & Reduced-Order State-Space Modeling of Wind Turbine Systems with Permanent-Magnet Synchronous Generator

Wind energy is an integral part of nowadays energy supply and one of the fastest growing sources of electricity in the world today. Accurate models for wind energy conversion systems (WECSs) are of key interest for the analysis and control design of present and future energy systems. Existing control-oriented WECSs models are subject to unstructured simplifications, which have not been discussed in literature so far. Thus, this technical note presents are thorough derivation of a physical state-space model for permanent magnet synchronous generator WECSs. The physical model considers all dynamic effects that significantly influence the system's power output, including the switching of the power electronics. Alternatively, the model is formulated in the $(a,b,c)$- and $(d,q)$-reference frame. Secondly, a complete control and operation management system for the wind regimes II and III and the transition between the regimes is presented. The control takes practical effects such as input saturation and integral windup into account. Thirdly, by a structured model reduction procedure, two state-space models of WECS with reduced complexity are derived: a non-switching model and a non-switching reduced-order model. The validity of the models is illustrated and compared through a numerical simulation study.Comment: 23 pages, 11 figure

Softness dependence of the Anomalies for the Continuous Shouldered Well potential

By molecular dynamic simulations we study a system of particles interacting through a continuous isotropic pairwise core-softened potential consisting of a repulsive shoulder and an attractive well. The model displays a phase diagram with three fluid phases, a gas-liquid critical point, a liquid-liquid critical point, and anomalies in density, diffusion and structure. The hierarchy of the anomalies is the same as for water. We study the effect on the anomalies of varying the softness of the potential. We find that, making the soft-core steeper, the regions of density and diffusion anomalies contract in the T - {\rho} plane, while the region of structural anomaly is weakly affected. Therefore, a liquid can have anomalous structural behavior without density or diffusion anomalies. We show that, by considering as effective distances those corresponding to the maxima of the first two peaks of the radial distribution function g(r) in the high-density liquid, we can generalize to continuous two-scales potentials a criterion for the occurrence of the anomalies of density and diffusion, originally proposed for discontinuous potentials. We observe that the knowledge of the structural behavior within the first two coordination shells of the liquid is not enough to establish the occurrence of the anomalies. By introducing the density derivative of the the cumulative order integral of the excess entropy we show that the anomalous behavior is regulated by the structural order at distances as large as the fourth coordination shell. By comparing the results for different softness of the potential, we conclude that the disappearing of the density and diffusion anomalies for the steeper potentials is due to a more structured short-range order. All these results increase our understanding on how, knowing the interaction potential, we can evaluate the possible presence of anomalies for a liquid

Grapheme-phoneme learning in an unknown orthography: a study in typical reading and dyslexic children

In this study, we examined the learning of new grapheme-phoneme correspondences in individuals with and without dyslexia. Additionally, we investigated the relation between grapheme-phoneme learning and measures of phonological awareness, orthographic knowledge and rapid automatized naming, with a focus on the unique joint variance of grapheme-phoneme learning to word and non-word reading achievement. Training of grapheme-phoneme associations consisted of a 20-min training program in which eight novel letters (Hebrew) needed to be paired with speech sounds taken from the participant's native language (Dutch). Eighty-four third grade students, of whom 20 were diagnosed with dyslexia, participated in the training and testing. Our results indicate a reduced ability of dyslexic readers in applying newly learned grapheme-phoneme correspondences while reading words which consist of these novel letters. However, we did not observe a significant independent contribution of grapheme-phoneme learning to reading outcomes. Alternatively, results from the regression analysis indicate that failure to read may be due to differences in phonological and/or orthographic knowledge but not to differences in the grapheme-phoneme-conversion process itself