2,734 research outputs found

    AJAE Appendix: Deriving a Flexible Mixed Demand System: The Normalized Quadratic Model

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    The material contained herein is supplementary to the article named in the title and published in the American Journal of Agricultural Economics, Volume 89, Number 4, November 2007.Demand and Price Analysis,

    On the format for parameters

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    Notes on cartography and further explanation

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    This article addresses one particular aspect of the cartographic enterprise, the cartographic study of the left periphery of the clause, the system of criteria, and the "syntacticisation” of scope-discourse semantics that rich and detailed syntactic maps make possible. I will compare this theoretical option with the conceivable alternative, the "pragmaticization” of a radically impoverished syntax, and will discuss some simple kinds of empirical evidence bearing on the choice between these alternative perspectives. I will then turn to the issue of whether the properties of the functional sequence (ordering, cooccurrence restrictions) are amenable to "further explanations” in terms of more basic principles constraining linguistic computations. I will argue that the search for deeper explanations is an integral part of the cartographic endeavour: it presupposes the establishment of reliable maps, and nourishes the pursuit of further cartographic questions. I will conclude by illustrating the issue of further explanation by comparing certain properties of topicalization in English and Italian, in particular the fact that DP topics are fundamentally unique in English, while they can be freely reiterated in Italian. This pattern can be plausibly traced back to intervention locality, once certain independent properties distinguishing Italian and English topicalization are taken into accoun

    Frequency shifts in natural vibrations in pantographic metamaterials under biaxial tests

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    In this paper a 2D continuum model, thought as the homogenized limit of a microstructured pantographic sheet, is studied. The microstructure is characterized by two families of parallel fibers, whose deformation measures account for bending, elongation and relative rotation of the fibers. The deformation energy density of the homogenized model depends on both first and second gradients of the displacement. Modal analysis is performed in order to assess the peculiarities of the dynamic behavior of higher gradient models, and in particular the difference, with respect to classical laminae, in the dependence of the eigenfrequencies on the stiffness

    On some properties of subjects and topics

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    Linguistic Knowledge and Unconscious Computations

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    Abstract: The open-ended character of natural languages calls for the hypothesis that humans are endowed with a recursive procedure generating sentences which are hierarchically organized. Structural relations such as c-command, expressed on hierarchical sentential representations, determine all sorts of formal and interpretive properties of sentences. The relevant computational principles are well beyond the reach of conscious introspection, so that studying such properties requires the formulation of precise formal hypotheses, and empirically testing them. This article illustrates all these aspects of linguistic research through the discussion of non-coreference effects. The article argues in favor of the formal linguistic approach based on hierarchical structures, and against alternatives based on vague notions of “analogical generalization”, and/or exploiting mere linear order. In the final part, the issue of cross-linguistic invariance and variation of non-coreference effects is addressed.Keywords: Linguistic Knowledge; Morphosyntactic Properties; Unconscious Computations; Coreference; Linguistic Representations Conoscenza linguistica e computazioni inconsceRiassunto: Il carattere aperto del linguaggio naturale avvalora l’ipotesi che gli esseri umani siano dotati di una procedura ricorsiva che genera frasi gerarchicamente organizzate. Relazioni strutturali come il c-comando, espresse su rappresentazioni frasali gerarchiche, determinano tutte le proprietà formali e interpretative delle frasi. I principi computazionali rilevanti sono totalmente al di fuori della portata della coscienza introspettiva e così lo studio di tali proprietà richiede la formulazione di precise ipotesi formali e la loro verifica sperimentale. Questo articolo illustra tutti questi aspetti della ricerca linguistica, esaminando gli effetti di non-coreferenza. Si argomenta in favore dell’approccio linguistico formale basato su strutture gerarchiche e contro alternative basate su vaghe nozioni di “generalizzazione analogica” e/o che impiegano il semplice ordine lineare. Nella parte finale si affronta il tema dell’invarianza e della variazione cross-linguistica degli effetti di non-coreferenza.Parole chiave: Conoscenza linguistica; Proprietà morfosintattiche; Computazioni inconsce; Coreferenzialità; Rappresentazioni linguistich

    Widening agreement processing: a matter of time, features and distance

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    Published online: 08 Mar 2018Existing psycholinguistic models typically describe agreement relations as monolithic phenomena amounting to mechanisms that check mere feature consistency. This eye-tracking study aimed at widening this perspective by investigating the time spent reading subject-verb (number, person) and adverb-verb (tense) violations on an inflected verb during sentence comprehension in Spanish. Results suggest that (i) distinct processing mechanisms underlie the analysis of subject-verb and adverb-verb relations, (ii) the parser is sensitive to the different interpretive properties that characterise the person, number and tense features encoded in the verb (i.e. anchoring to discourse for person and tense interpretation, as opposed to anchoring to cardinality information for number), and (iii) the (local, distal) position of the agreement controller with respect to the verb affects the interpretation of these dependencies. An account is proposed that capitalises on the importance of enriching current sentence processing formalizations using a feature and relation-based approach.S.M acknowledges funding from the Gipuzkoa Fellowship Program, from grants FFI2016-76432 and SEV-2015-490, Severo Ochoa Programme for Centres/Units of excellence in R&D awarded by the Spanish Ministry of Industry, Economy and Competitiveness (MINECO). L.R. acknowledges support from the ERC Advanced Grant n. 340297 “SynCart”

    Abstract knowledge of word order by 19 months: An eye-tracking study

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    Word order is one of the earliest aspects of grammar that the child acquires, because her early utterances already respect the basic word order of the target language. However, the question of the nature of early syntactic representations is subject to debate. Approaches inspired by formal syntax assume that the head-complement order, differentiating verb-object and object-verb languages, is represented very early on in an abstract, rulelike format. In contrast, constructivist theories assume that it is initially encoded as lexicalized, verb-specific knowledge. In order to address this issue experimentally, we combined the preferential looking paradigm using pseudoverbs with the weird word order paradigm adapted to comprehension. The results, based on highly reliable, coder-independent eye-tracking measures, provide the first direct evidence that as early as 19 months French-speaking infants have an abstract representation of the word order of their languag

    A unified framework for machine learning collective variables for enhanced sampling simulations: mlcolvar\texttt{mlcolvar}

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    Identifying a reduced set of collective variables is critical for understanding atomistic simulations and accelerating them through enhanced sampling techniques. Recently, several methods have been proposed to learn these variables directly from atomistic data. Depending on the type of data available, the learning process can be framed as dimensionality reduction, classification of metastable states or identification of slow modes. Here we present mlcolvar\texttt{mlcolvar}, a Python library that simplifies the construction of these variables and their use in the context of enhanced sampling through a contributed interface to the PLUMED software. The library is organized modularly to facilitate the extension and cross-contamination of these methodologies. In this spirit, we developed a general multi-task learning framework in which multiple objective functions and data from different simulations can be combined to improve the collective variables. The library's versatility is demonstrated through simple examples that are prototypical of realistic scenarios
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