Effects of Additional Tasks on Language Perception: An Event-Related Brain Potential Investigation.

The authors investigated effects of task and overlapping processing load on semantic processing. In 3 experiments the brain potential component N400 was elicited by synonymous and nonsynonymous spoken noun pairs that were to be classified according to semantic relatedness. The time course of the N400 component to the nouns was delayed, and its amplitude was reduced when additional tasks had to be performed. The delay increased with temporal overlap and was more pronounced for language-related than for spatial additional tasks. Delays of N400 were also caused by a compatibility manipulation in the additional tasks. Theoretical accounts of the observed interference of overlapping tasks with language perception in terms of attentional shifts were discarded. Explanations in terms of resource sharing and single channel processing are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Peculiarities in the morphology of ge island array on Si(100) at a subcritical thickness of the deposited Ge layer

Experiments revealed the formation of Ge islands on a Si(100) surface at an effective thickness of the deposited germanium layer below the critical value for the transition from two-to three-dimensional growth. The number density of Ge islands in the array was 3×10⁸ cm^?2. The results are interpreted within the framework of a kinetic model of the island formation in heteroepitaxial systems with lattice mismatch.     

Online help-seeking in communities of practice: Modeling the acceptance of conceptual artifacts

Interactive online help systems are considered to be a fruitful supplement to traditional IT helpdesks, which are often overloaded. They often comprise user-generated FAQ collections playing the role of technology-based conceptual artifacts. Two main questions arise: how the conceptual artifacts should be used, and which factors influence their acceptance in a community of practice (CoP). Firstly, this paper offers a theoretical frame and a usage scenario for technology-based conceptual artifacts against the theoretical background of the academic help-seeking and CoP approach. Each of the two approaches is extensively covered by psychological and educational research literature, however their combination is not yet sufficiently investigated. Secondly, the paper proposes a research model explaining the acceptance of conceptual artifacts. The model includes users' expectations toward the artifact, perceived social influence and users' roles in the CoP as predictors of artifact use intention and actual usage. A correlational study conducted in an academic software users' CoP and involving structural equations modeling validates the model, suggesting thus a research line that is worth further pursuing. For educational practice, the study suggests three ways of supporting knowledge sharing in CoPs, i.e. use of technology-based conceptual artifacts, roles and division of labor, and purposeful communication in CoPs.     

Simulation and Optimization of the Implementation Costs for the Last Mile of Fiber Optic Networks

The access net domain (last mile) still represents the bottleneck of present fiber optic network architectures. Although the investment volume in this domain definitely exceeds the costs of core- and distribution nets, network carriers hardly utilize intelligent planning tools for anticipatory investment decisions and cost optimization in this area. This article presents the methods behind a strategic planning and optimization tool which was developed in cooperation with renowned european city carriers. Based on real world geoinformation data a hierarchical optimization routine using methods of combinatorial optimization and graph theory allows a cost optimized simulation for the laying of fiber optic cables in the access net domain. Beside the used methodology an industrial benchmark project shows a typical scenario of application.