The toxicity of chlorpyrifos towards differentiating mouse N2a neuroblastoma cells

The aim of this work was to study the effects of chlorpyrifos (CPF) on the outgrowth of axons by differentiating mouse N2a neuroblastoma cells. This was achieved by morphological, Western blotting and enzymatic analyses of cells induced to differentiate in the presence and absence of CPF added either at the same time (co-differentiation) or 16 h after (post-differentiation) the induction of cell differentiation. The outgrowth of axon-like processes was impaired following 4 or 8 h exposure to CPF in both co- and post-differentiation experiments. Western blotting analysis revealed reduced levels of neurofilament heavy chain (NF-H) following 8 h of exposure but no significant effect at 4 h under both co- and post-differentiation conditions. By contrast, levels of the heat shock protein HSP-70 were raised at both time points, but only in co-differentiation experiments. Neuropathy target esterase (NTE) activity was lower than controls following 4 or 8 h of exposure under co-differentiation conditions, but not under any post-differentiation conditions. The results suggest that the inhibition of axon production and maintenance by CPF in differentiating N2a cells may involve multiple targets, which are different under co- and post-differentiation conditions

Nonlinear forecasting of the generalised Kuramoto-Sivashinsky equation

We study the emergence of pattern formation and chaotic dynamics in the one-dimensional (1D) generalized Kuramoto-Sivashinsky (gKS) equation by means of a time-series analysis, in particular a nonlinear forecasting method which is based on concepts from chaos theory and appropriate statistical methods. We analyze two types of temporal signals, a local one and a global one, finding in both cases that the dynamical state of the gKS solution undergoes a transition from high dimensional chaos to periodic pulsed oscillations through low dimensional deterministic chaos with increasing the control parameter of the system. Our results demonstrate that the proposed nonlinear forecasting methodology allows to elucidate the dynamics of the system in terms of its predictability properties

P3 amplitude indexes the degree of similarity-based interference in memory retrieval during sentence comprehension

Unitary memory models postulate a direct content-addressable (cuebased) retrieval in working and longterm memory Cue-based retrieval suffers from similarity-based interference. It increases with increasing cue overlap. The P300 effect correlates with memory retrieval in non-linguistic tasks. Amplitude is modulated by the number of involved features. The present study: is the P300 amplitude sensitive to the degree of similarity-based interference in memory retrieval during language comprehension? 2 ERP experiments investigated interference in memory retrieval in sluicing construction

The role of individual and social variables in task performance.

This paper reports on a data-based study in which we explored - as part of a larger-scale British-Hungarian research project - the effects of a number of affective and social variables on foreign language (L2) learners’ engagement in oral argumentative tasks. The assumption underlying the investigation was that students’ verbal behaviour in oral task situations is partly determined by a number of non-linguistic and non-cognitive factors whose examination may constitute a potentially fruitful extension of existing task-based research paradigms. The independent variables in the study included various aspects of L2 motivation and several factors characterizing the learner groups the participating students were members of (such as group cohesiveness and intermember relations), as well as the learners’ L2 proficiency and ‘willingness to communicate’ in their L1. The dependent variables involved objective measures of the students’ language output in two oral argumentative tasks (one in the learners’ L1, the other in their L2): the quantity of speech and the number of turns produced by the speakers. The results provide insights into the interrelationship of the multiple variables determining the learners’ task engagement, and suggest a multi-level construct whereby some independent variables only come into force when certain conditions have been met