7,597 research outputs found
On Myosin II dynamics in the presence of external loads
We address the controversial hot question concerning the validity of the
loose coupling versus the lever-arm theories in the actomyosin dynamics by
re-interpreting and extending the phenomenological washboard potential model
proposed by some of us in a previous paper. In this new model a Brownian motion
harnessing thermal energy is assumed to co-exist with the deterministic swing
of the lever-arm, to yield an excellent fit of the set of data obtained by some
of us on the sliding of Myosin II heads on immobilized actin filaments under
various load conditions. Our theoretical arguments are complemented by accurate
numerical simulations, and the robustness of the model is tested via different
choices of parameters and potential profiles.Comment: 6 figures, 8 tables, to appear on Biosystem
Prosodic constituents in the representation of consonantal sequences in Polish
The aim of this paper is to show what role prosodic constituents, especially the foot and the prosodic word play in Polish phonology. The focus is placed on their function in the representation of extrasyllabic consonants in word-initial, word-medial, and word-final positions.
The paper is organized as follows. In the first section, I show that the foot and the prosodic word are well-motivated prosodic constituents in Polish prosody. In the second part, I discuss consonant clusters in Polish focussing on segments that are not parsed into a syllable due to violations of the Sonority Sequencing Generalisation, i.e. extrasyllabic segments. Finally, I analyze possible representations of the extrasyllabic consonants and conclude that both the foot and the prosodic word play a crucial role in terms of licensing. My proposal differs from the ones by Rubach and Booij (1990b) and Rubach (1997) in that I argue that the word-initial sonorants traditionally called extrasyllabic are licenced by the foot and not by the prosodic word (cf. Rubach and Booij (1990b)) or the syllable (cf. Rubach (1997)). For my analysis I adopt the framework of Optimality Theory, cf. McCarthy and Prince (1993), Prince and Smolensky (1993), in which derivational levels are abandoned and only surface representations are evaluated by means of universal constraints
Asymmetry in presupposition projection: The case of conjunction
Is the basic mechanism behind presupposition projection fundamentally asymmetric
or symmetric? This is a basic question for the theory of presupposition, which also
bears on broader issues concerning the source of asymmetries observed in natural
language: are these simply rooted in superficial asymmetries of language use—
language use unfolds in time, which we experience as fundamentally asymmetric—
or can they be, at least in part, directly referenced in linguistic knowledge and
representations? In this paper we aim to make progress on these questions by
exploring presupposition projection across conjunction, which has typically been
taken as a central piece of evidence that presupposition projection is asymmetric.
As a number of authors have recently pointed out, however, whether or not this
conclusion is warranted is not clear once we take into account independent issues of
redundancy. Building on previous work by Chemla & Schlenker (2012) and Schwarz
(2015), we approach this question experimentally by using an inference task which
controls for redundancy and presupposition suspension. We find strong evidence for
left-to-right filtering across conjunctions, but no evidence for right-to-left filtering,
suggesting that, at least as a default, presupposition projection across conjunction is
indeed asymmetric
On Left and Right Dislocation: A Dynamic Perspective
The paper argues that by modelling the incremental and left-right process of interpretation as a process of growth of logical form (representing logical forms as trees), an integrated typology of left-dislocation and right-dislocation phenomena becomes available, bringing out not merely the similarities between these types of phenomena, but also their asymmetry. The data covered include hanging topic left dislocation, clitic left dislocation, left dislocation, pronoun doubling, expletives, extraposition, and right node raising, with each set of data analysed in terms of general principles of tree growth. In the light of the success in providing a characterisation of the asymmetry between left and right periphery phenomena, a result not achieved in more wellknown formalisms, the paper concludes that grammar formalisms should model the dynamics of language processing in time.Articl
The role of the language production system in shaping grammars.
We argue for an extension of the proposal that grammars are in part shaped by processing systems. Our extension focuses on production, and we use that to explore explanations for certain subject/object asymmetries in extraction structures
Anaphor resolution and the scope of syntactic constraints
An anaphor resolution algorithm is presented which relies on a combination of strategies for narrowing down and selecting from antecedent sets for re exive pronouns, nonre exive pronouns, and common nouns. The work focuses on syntactic restrictions which are derived from Chomsky's Binding Theory. It is discussed how these constraints can be incorporated adequately in an anaphor resolution algorithm. Moreover, by showing that pragmatic inferences may be necessary, the limits of syntactic restrictions are elucidated
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