Feedback effects on the current correlations in Y-shaped conductors

We study current fluctuations in a Y-shaped conductor connected to external leads with finite impedances. We show that, due to voltage fluctuations in the circuit, the moments of the transferred charges cannot be obtained from simple rescaling of the bare values already in the second moments. The cross-correlation between the output terminals can change from negative to positive under certain parameter regimes.Comment: 4 pages, figures attached separatel

Dual input and learnability: Null objects in Cantonese-English bilingual children

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Unbalanced bilingual acquisition as a mechanism of grammatical change

Bilingual first language acquisition (BFLA) has been considered a possible mechanism of contact-induced change in several recent studies (Siegel, 2008, p. 117; Satterfield, 2005, p. 2075; Thomason, 2001, p. 148; Yip & Matthews, 2007, p.15). There is as yet little consensus on the question, with divergent views regarding both BFLA at the individual level and the implications for language change at the community level.published_or_final_versio

Code-Mixing and Mixed Verbs in Cantonese-English Bilingual Children: Input and Innovation

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Relative clauses in Cantonese-English bilingual children: Typological challenges and processing motivations

Findings from a longitudinal study of bilingual children acquiring Cantonese and English pose a challenge to the noun phrase accessibility hierarchy (NPAH; Keenan & Comrie, 1977), which predicts that object relatives should not be acquired before subject relatives. In the children's Cantonese, object relatives emerged earlier than or simultaneously with subject relatives, and in their English, prenominal relatives based on Cantonese emerged first, with object relatives followed by subject relatives. These findings are discussed in light of findings on the typology and acquisition of relative clauses (RCs) and the underlying processing motivations of the NPAH. Prenominal object relatives in the bilingual children's Cantonese and English have the same word order as main clauses and can be analyzed as internally headed RCs. The reconceptualization of RCs as attributive clauses (Comrie, 1998a, 1998b, 2002) is supported by children's early RCs lacking a strict grammatical relationship between the head noun and the predicate. Furthermore, as observed by Diessel and Tomasello (2000, 2005) for English, bilingual children's earliest RCs consist of isolated noun phrases (NPs). The early object relatives produced by bilingual children are therefore essentially NPs with the linear order of a main clause, resulting in a configuration that is conducive to early production. © 2007 Cambridge University Press.published_or_final_versio

Bilingual first language acquisition and the mechanisms of substrate influence

This paper draws together two fields of study, early bilingual acquisition and language contact, showing close parallels between transfer at the individual and substrate influence at the societal level. Romaine (1996) emphasizes that ‘the bilingual individual is the ultimate locus of language contact’, while Thomason (2001) considers bilingual first language acquisition as a mechanism of contact-induced change which has been relatively little studied to date. Pursuing these two ideas, we show how the developmental patterns in bilingual Cantonese-English children parallel prominent features in a contact variety of English, namely Singapore Colloquial English, spoken by a community of native speakers (Gupta 1994). At the individual ...postprin

Syntactic transfer in a Cantonese-English bilingual child

Research on early bilingual development has suggested that syntactic transfer in bilingual acquisition is dependent on patterns of dominance and properties of the dual input the child is exposed to. In a case study of a Hong Kong bilingual child we present evidence of transfer from Cantonese to English in three areas where the two languages contrast typologically: wh-in-situ interrogatives, null objects and prenominal relatives are observed at a period when Cantonese is dominant as measured by MLUw. Comparisons with monolingual development show both qualitative and quantitative differences attributable to transfer. Language dominance is seen as the major determinant of transfer, with input ambiguity playing a role in the domain of null objects. While two distinct and separate linguistic systems are simultaneously developing in the bilingual mind, the pervasiveness of transfer implies a high degree of interaction between them. The findings show that the bilingual subject in our case study has taken a different path from monolinguals toward the target.published_or_final_versio

Assessing language dominance in bilingual acquisition: a case for mean length utterance differentials

The notion of language dominance is often defined in terms of proficiency. We distinguish dominance, as a property of the bilingual mind and a concept of language knowledge, from proficiency, as a concept of language use. We discuss ways in which language dominance may be assessed, with a focus on measures of mean length of utterance (MLU). Comparison of MLU in the child's 2 languages is subject to questions of comparability across languages. Using the Hong Kong Bilingual corpus of Cantonese–English children's development, we show how MLU differentials can be a viable measure of dominance that captures asymmetrical development where there is an imbalance between the child's 2 languages. The directionality of syntactic transfer goes primarily from the language with higher MLU value to the language with lower MLU value, and the MLU differential matches the pervasiveness of transfer effects, as in the case of null objects discussed here: The greater the differential, the more frequent the occurrence of null objects. Cantonese-dominant children with a larger MLU differential use null objects more frequently than those with a lower MLU differential. In our case studies, MLU differentials also matched with language preferences and silent periods but did not predict the directionality of code-mixing.published_or_final_versio

Bilingualism and language acquisition in early childhood: research and application

Distinguished Speakers Lecture Seriespostprin

ac Josephson effect in asymmetric superconducting quantum point contacts

We investigate ac Josephson effects between two superconductors connected by a single-mode quantum point contact, where the gap amplitudes in the two superconductors are unequal. In these systems, it was found in previous studies on the dc effects that, besides the Andreev bound-states, the continuum states can also contribute to the current. Using the quasiclassical formulation, we calculate the current-voltage characteristics for general transmission $D$ of the point contact. To emphasize bound versus continuum states, we examine in detail the low bias, ballistic (D=1) limit. It is shown that in this limit the current-voltage characteristics can be determined from the current-phase relation, if we pay particular attention to the different behaviors of these states under the bias voltage. For unequal gap configurations, the continuum states give rise to non-zero sine components. We also demonstrate that in this limit the temperature dependence of the dc component follows $\tanh(\Delta_s/2T)$, where $\Delta_s$ is the smaller gap, with the contribution coming entirely from the bound state.Comment: To appear in PR