Default aspect based on state change

The paper shows that a single aspect operator successfully generates the interpretations of Russian perfective and imperfective forms, if the following requirements are met. First, the default aspect operator has to be based on the notion of state change. Secondly, the output of the operator is filtered by semantic and morphological blocking constraints.

Visual field of the mud crab, Scylla tranquebarica and the whiteleg shrimp, Litopenaeus vannamei

The previous behavioural studies on vision of decapod crustaceans were often based on the assumption that the visual field of the test animals was all around and there was little or no blind area above or to the rear of the animals. In the present study, we determined the visual field of the wild captured purple mud crab (Scylla tranquebarica) and the farmed whiteleg shrimp (Litopenaeus vannamei) by eliminating the directions in which vision is anatomically blocked in all directions around the eyes. The mud crab had the visual field covering the entire visual world except for the ventral-most blind area. The whiteleg shrimp has the visual filed with a 66Ëš binocular field and can see all around but is morphologically blocked by the scaphocerite extended forward between the eyes. While the transparent scaphocerites transmit 80 % of light from 400 to 700 nm wavelengths, an object seen through the scaphocerites is faded due to the light refraction, indicating that the morphological blocking is not always negligible. The trait of these visual fields should be taken into consideration in the design of visual behaviour experiments.

On dissolving morphological long distance dependencies in Russian verbs

This paper presents implementational issues of a finite-state approach for two crucial parts of Russian verbal morphology: Aspect formation and deverbal nominalization with nie based on aspect formation. The first process involves morphological blocking in order to avoid overgeneralization and is implemented with the xfst- tools via combining two powerful mechanisms - flag diacritics and rewrite rules. This considerably helps reducing the network size while having only small effects on processing time. Deverbal nominalization with nie has also been considered as involving some form of blocking. However, we show how to reanalyze this morphological process as a simple case of phonological neutralization which fits into a broader theory of the Russian sound system. The analysis and implementation presented here are thus theoretically consistent while maintaining implementational effectiveness.