bluuebunny/crossref_metadata_2025_split huggingface dataset:
The bilingual lexicon: implications for studies of language choice
Authors: Quay Suzanne 
Published: September 2008

ABSTRACTLexical gaps in vocabulary development have been acknowledged as a reason for language mixing in young bilingual children. In spite of this, most studies do not take into account whether young bilinguals have the lexical resources to make a choice between their two languages. Inferences are nevertheless still being made about whether or not young bilinguals differentiate between their two languages based on language choice. It is widely believed, however, that young bilinguals do not have the resources to make lexical choices at a pre-syntactic stage of development before age two. A bilingual case study of an infant acquiring Spanish and English from birth to age 1;10 is used to address this issue. Daily diary records and weekly video recordings in the two language contexts are used to construct the child's lexicon and to establish that translation equivalents that make possible language choice are available from the beginning of speech. The results are used to discuss the importance of translation equivalents in the bilingual lexicon for viable interpretations of language choice.
The use of props in a syntactic awareness task
Authors: Blackmore Amanda Marie , Pratt Chris , Dewsbury Alison 
Published: September 2008

ABSTRACTThe study investigated the effects of using props to illustrate the meaning of sentences in a syntactic awareness task in which subjects were required to correct ungrammatical sentences. Forty preschool children (aged 4;11 to 5;11) were asked to correct 20 sentences, 10 of which were illustrated using props, and 10 of which were not. Children scored significantly higher in the props condition though the proportion of meaning-changing errors to total errors was not significantly lower in this condition. It is argued that the use of props, by providing contextual support, reduces the processing capacity required to complete the task.
Early lexical acquisition and the vocabulary spurt: a response to Goldfield & Reznick
Authors: Mervis Carolyn B. , Bertrand Jacquelyn 
Published: September 2008

ABSTRACTVocabulary development of three children (aged 1;6–1;8 at the start of the study) who had not begun to evidence a vocabulary spurt even though their productive vocabularies already included well over 50 words was followed to determine if these children eventually would have a vocabulary spurt. All three children evidenced a spurt, beginning at a mean productive vocabulary size of 112 words. The vocabulary spurt occurred at about the same time as the children first demonstrated the ability to sort objects exhaustively and to fast map new object names. Results are discussed in the context of Goldfield & Reznick's (1990; Reznick & Goldfield, 1992) argument that a substantial proportion of children never evidence a vocabulary spurt.
The acquisition of phonology by Cantonese-speaking children
Authors: So Lydia K. H. , Dodd Barbara J. 
Published: September 2008

ABSTRACTLittle is known about the acquisition of phonology by children learning Cantonese as their first language. This paper describes the phoneme repertoires and phonological error patterns used by 268 Cantonese-speaking children aged 2;0 to 6;0, as well as a longitudinal study of tone acquisition by four children aged 1;2 to 2;0. Children had mastered the contrastive use of tones and vowels by two years. While the order of acquisition of consonants was similar to that reported for English, the rate of acquisition was more rapid. The developmental error patterns used by more than 10% of children are also reported as common in other languages. However, specific rules associated with Cantonese phonology were also identified. Few phonological errors were made after age four. The results are consistent with the hypothesis that the ambient language influences the implementation of universal tendencies in phonological acquisition.
Early acquisition of verbs in Korean: a cross-linguistic study
Authors: Choi Soonja , Gopnik Alison 
Published: September 2008

ABSTRACTThis cross-linguistic study investigates children's early lexical development in English and Korean, and compares caregivers' linguistic input in the two languages. In Study 1, the lexical development of nine Korean children was followed from 1;2 to 1;10 by monthly visits and maternal reports. These Korean data were compared to previously collected English longitudinal data. We find that: (1) Korean children as young as 1;3 use verbs productively with appropriate inflections. (2) Seven of the nine children show a verb spurt at around 1;7; for six of these children the verb spurt occurs before the noun spurt. No such early verb spurt is found in the English data. Unlike in English, both verbs and nouns in Korean are dominant categories from the single-word stage. (3) Korean children express language-specific distinctions of locative actions with verbs. Study 2, a crosslinguistic study of caregivers' input in English and Korean, shows that Korean mothers provide more action verbs but fewer object nouns than American mothers. Also, Korean mothers engage in activity-oriented discourse significantly more than American mothers. Our study suggests that verbs are accessible to children from the beginning, and that they may be acquired early in children who are encouraged to do so by their language-specific grammar and input.
Reference states and reversals: undoing actions with verbs
Authors: Clark Eve V. , Carpenter Kathie L. , Deutsch Werner 
Published: September 2008

ABSTRACTThe purpose of these studies is to characterize children's conception of reversal and its relation to a reference state. A reversal is the move from one state to some prior state of affairs. For example, shoes that have been TIED can be UNTIED, parcels WRAPPED then UNWRAPPED, and dishes COVERED then UNCOVERED. The present studies were designed to find out how children (aged 1;0 to 5;0) describe reversals of action that restore objects to a prior, less constrained, state. In English, the prefix un- offers the most productive device for this, but, initially, children rely on a verb like open, on general purpose undo, and on particles like out and off, As they acquire un-, English-speaking children must learn that this prefix applies primarily to verbs for change-of-state, often for enclosing, covering and attaching. In German, there is no reversal prefix, but there are productive particles. German-speaking children also begin with a verb like open and then turn to verb particles on a course similar to that in English to express reversals.
An examination of similarity neighbourhoods in young children's receptive vocabularies
Authors: Charles-Luce Jan , Luce Paul A. 
Published: September 2008

ABSTRACTBased on an analysis of similarity neighbourhoods of words in children's lexicons, Dollaghan (1994) argues that because of the degree of phonological overlap among lexical items in memory, children must perform detailed acoustic-phonetic analyses in order to recognize spoken words. This is in contradiction to Charles-Luce & Luce (1990), who reported that the similarity neighbourhoods in younger children's expressive lexicons are sparse relative to older children's and adult lexicons and that young children may be able to use more global word recognition strategies. The current investigation re-examined these issues. Similarity neighbourhoods of young children's RECEPTIVE vocabularies were analysed for three-phoneme, four-phoneme and five-phoneme words. The pattern of the original results from Charles-Luce & Luce (1990) was replicated.
Context-sensitive underspecification and the acquisition of phonemic contrasts
Authors: Dinnsen Daniel A. 
Published: September 2008

ABSTRACTSeveral competing proposals for the (under)specification of phonological representations are evaluated against the facts of phonemic acquisition. Longitudinal evidence relating to the emergence of a voice contrast in the well-documented study of Amahl (from age 2;2 to 3;11) is reconsidered. Neither contrastive specification nor context-free radical underspecification is capable of accounting for the facts. The problem is in the characterization of the change in the status of a feature from being noncontrastive and conditioned by context at one stage to being contrastive with phonetic effects that diffuse gradually through the lexicon. Both frameworks must treat as accidental the persistence of the early substitution pattern and require the postulation of wholesale changes in underlying representations, where these changes do not accord well with the observed phonetic changes or with the facts available to the learner. Context-sensitive radical underspecification provides a plausible account of each stage and the transition between stages with minimal grammar change.
The development of syntactic subjects in Portuguese-speaking children
Authors: Valian Virginia , Eisenberg Zena 
Published: September 2008

ABSTRACTIn order to separate competence and performance factors in acquisition of knowledge of syntactic subjects, we audiotaped and analysed the spontaneous speech of 20 Portuguese-speaking two-year-olds in natural conversation with Portuguese-speaking adults. We separated the children into three groups based on Mean Length of Utterance in Words: 1·5–1·99; 2·0–2·99; 3·0–4·99. Our cross-sectional data demonstrated that Portuguese-speaking children increased their use of subjects from 28% in the lowest-MLUW group to 57% in the highest-MLUW group. The children in the highest-MLUW group almost perfectly matched the adult speakers in the study on every measure. The increase in children's use of subjects was primarily due to an increase in the use of pronominal subjects. A comparison between Portuguese- and English-speaking children suggests that adult competence about the status of subjects is present at the onset of combinatorial speech, as shown by differential production of subjects. Each group also experiences performance limitations, as shown by the increase in subject use as development proceeds.
Early passive acquisition in Inuktitut
Authors: Allen Shanley E. M. , Crago Martha B. 
Published: September 2008

ABSTRACTPassive structures are typically assumed to be one of the later acquired constructions in child language. English-speaking children have been shown to produce and comprehend their first simple passive structures productively by about age four and to master more complex structures by about age nine. Recent crosslinguistic data have shown that this pattern may not hold across languages of varying structures. This paper presents data from four Inuit children aged 2;0 to 3;6 that shows relatively early acquisition of both simple and complex forms of the passive. Within this age range children are productively producing truncated, full, action and experiential passives. Some possible reasons for this precociousness are explored including adult input and language structure.
Colour term knowledge in two-year-olds: evidence for early competence
Authors: Shatz Marilyn , Behrend Douglas , Gelman Susan A. , Ebeling Karen S. 
Published: September 2008

ABSTRACTIt is commonly believed that colour terms are acquired unusually slowly. However, several recent studies suggest that preschoolers have more colour term knowledge than previously believed. In two studies, we investigated the colour term knowledge of 49 two-year-olds and the influence of schooling on their colour term acquisition. Both studies revealed considerable knowledge in such young children. A longitudinal comparison of children with and without school experience in Study 2 indicated that the higher performance of the school group could not be accounted for by differences predating that group's experience. In reviewing the evidence from the children's performance, we conclude that contemporary children's early and frequent experience with colour terms may account for this cohort's improved performance over previous generations of children.
Developmental changes in the incidence and likelihood of simultaneous talk during the first two years: a question of function
Authors: Elias Gordon , Broerse Jack 
Published: September 2008

ABSTRACTGlobal tendencies for the relative absence of covocalization (simul- taneous talk) have been identified in both conversations between adult partners and conversations between mothers and their infants; in each case, the alternating mode in which one partner speaks at a time is predominant. The present investigation examined the timing of the partners' talk in mother-infant engagements over infant age to determine whether: (a) variations occur in the incidence of the alternating mode; and (b) variations occur in the extent to which the alternating mode predominates. Conversations involving a total of 48 mothers and their infants aged from 0;3 to 2;0 were investigated at each of eight infant ages (0;3, 0;6, 0;9, 1;0, 153, 1;6, 1;9 and 2;0). The results indicated that, within a global tendency for the relative absence of covocalization, there was: (a) a curvilinear tendency for the incidence of covocalization to decrease over the first 18 months, and then to increase; and (b) a linear tendency for the extent to which the alternating mode predominates to increase over age. These changes are interpreted as reflecting the facilitative effects of covocalization in the case of young preverbal infants, and the need for the alternating, turn-taking pattern to predominate as mutual comprehension becomes possible in conversations between mothers and their older infants.
Hele–Shaw flows with a free boundary produced by multipoles
Authors: Entov Vladimir M. , Etingof Pavel I. , Kleinbock Dmitry Ya. 
Published: September 2008

We study Hele–Shaw flows with a moving boundary and multipole singularities. We find that such flows can be defined only on a finite time interval. Using a complex variable approach, we construct a family of explicit solutions for a single multipole. These solutions turn out to have the maximal possible lifetime in a certain class of solutions.We also discuss the generalized Hele-Shaw model in which surface tension at the moving boundary is considered, and develop a method of finding steady shapes. This method yields new one-parameter families of stationary solutions. In the Appendix we discuss a connection between these solutions and a variational problem of potential theory.
Asymptotic evaluation of oscillatory sums
Authors: Keller Joseph B. , Knessl Charles 
Published: September 2008

A stationary phase method is developed for the asymptotic evaluation, as R → ∞, of oscillatory sums of the formIt is extended to multidimensional sums. Numerical comparisons demonstrate the accuracy of the asymptotic approximations. The results are applied to the practical estimation of the number of lattice points in large domains in ℝ2.
The Stefan problem with surface tension in the three dimensional case with spherical symmetry: nonexistence of the classical solution
Authors: Meirmanov A. M. 
Published: September 2008

The Stefan problem with surface tension in the three-dimensional case with spherical symmetry is considered. We first establish the existence and uniqueness of the classical solution with surface tension and kinetic undercooling effects for all time, and then pass to the limit as the kinetic undercooling tends to zero. The limiting solution is the global-in-time weak solution and the local-in-time classical solution for the Stefan problem with surface tension. This solution cannot be the global-in-time classical solution. If S(t) is the radius of a solid ball in a supercooled liquid, then (1) there exists at least one point t* of discontinuity of the function S(t):or (2) the continuous function S(t) cannot be absolutely continuous, and it maps some zero-measure set of (t*, T*) onto some set of Ω with a strictly positive measure.
Existence and uniqueness of radially symmetric stationary points within the gradient theory of phase transitions
Authors: Niethammer Barbara S. 
Published: September 2008

We study radially symmetric stationary points of the functionalwhereudenotes the density of a fluid confined to a containerΩ, W(u)is the course-grain free energy and ε accounts for surface energy. Under the further assumption of small energy, that isfor small ε, we prove existence of precisely two solutions for the corresponding Euler-Lagrange equation. Each of these solutions is monotone in the radial direction and converges as ε→0 to one of two possible radially symmetric single interface minimizers ofE0. Our main tool is the method of matched asymptotic expansions from which we construct exact solutions.
Vortex annihilation in nonlinear heat flow for Ginzburg–Landau systems
Authors: Bauman Patricia , Chen Chao-Nien , Phillips Daniel , Sternberg Peter 
Published: September 2008

We consider the Cauchy problem for the systemwhere . Let e ∈ ℝ2 with |e| = 1. If u(x, 0) is smooth, bounded andwe prove u → e uniformly in x as t → ∞. Of particular interest is the motion of the zeros (vortices) of u. In this case, all zeros disappear after a finite time.
The Cahn–Hilliard equation with a concentration dependent mobility: motion by minus the Laplacian of the mean curvature
Authors: Cahn J. W. , Elliott C. M. , Novick-Cohen A. 
Published: September 2008

We show by using formal asymptotics that the zero level set of the solution to the Cahn–Hilliard equation with a concentration dependent mobility approximates to lowest order in ɛ. an interface evolving according to the geometric motion,(whereVis the normal velocity, Δ8is the surface Laplacian and κ is the mean curvature of the interface), both in the deep quench limit and when the temperature θ iswhere є2is the coefficient of gradient energy. Equation (0.1) may be viewed as motion by surface diffusion, and as a higher-order analogue of motion by mean curvature predicted by the bistable reaction-diffusion equation.
A sharp interface limit of the phase field equations: one-dimensional and axisymmetric
Authors: Stoth Barbara E. E. 
Published: September 2008

We study the singular limit of the dimensionless phase-field equationsWe consider two cases: either the space dimension is 1 and then ɛ tends to zero; or the solutions are radially symmetric and then both ɛ and α tend to zero. It turns out that, in the first case, the limiting functions solve the Stefan problem with kinetic undercooling, provided the initial temperature is small compared to the surface tension and the latent heat. In the second case, the limiting functions satisfy the Stefan problem coupled with the Gibbs–Thomson law for the melting temperature. We show, in addition, that the multiplicity of the interface is always one, in a sense to be explained at the end of § 1. As main tool we use energy type estimates, and prove that the formal first-order asymptotic expansion with respect to ɛ in fact gives an approximation of the exact solution. Our results hold without smoothness assumptions on the limiting Stefan problem.
Behaviour of hamster and mouse round spermatid nuclei incorporated into mature oocytes by electrofusion
Authors: Ogura Atsuo , Yanagimachi Ryuzo , Usui Noriko 
Published: September 2008

summaryRound spermatids of the hamster and mouse were electrofused with homologous mature oocytes to examine the behaviour of their nuclei within the ooplasm. A single spermatid was inserted in the perivitelline space of a mature oocyte and an electric fusion pulse given. In the hamster, the best spermatid-oocyte fusion took place when the oocytes were pretreated with neuraminidase, subjected to 30 s AC (2 MHz, 20 V/cm) followed by a single fusion DC pulse (3000 V-cm, 10 μs) and another 30 s AC current. Inclusion of micromolar Ca2+and Mg2+in the fusion medium was essential for oocyte activation. Under these conditions all oocytes were activated and 20–40% fused with spermatids. Of these fused oocytes only 5–10% had fully developed spermatid (male) and oocyte (female) pronuclei. In the rest the spermatid-derived pronuclei remained small throughout the pronuclear stage. However, nucleolus-like structures appearedde novoand DNA synthesis occurred in these small pronuclei. Regardless of the size of male pronuclei, chromosomes from the spermatid and oocyte appeared to mingle and participate in the first cleavage. About 70% of the fused oocytes developed into the 2-cell stage. Electrofusion of mouse oocytes with spermatids was less efficient. Even under the best conditions tested, less than 10% of the oocytes fused with spermatids. Here again, most spermatid nuclei remained small throughout the pronuclear stage.
Microinjection of FITC-dextran into mouse blastomeres to assess topical effects of zona photoablation
Authors: Li Leyi , Munne Santiago , Licciardi Frederick , Neev Joseph , Tadir Yona , Berns Michael , Godke Robert , Cohen Jacques 
Published: September 2008

SummaryThe objective of the current experiments was to investigate whether all or only some blastomeres from precompacted mouse embryos were affected by zona photoablation. The microbeam of xenon chloride excimer laser (308 nm) was guided through an inverted microscope (non-contact system). Topical effects of lasing were determined by microinjection of a vital fluorescent dye of high molecular weight (fluorescein isothiocyanate [FITC] dextran) into the cell immediately adjacent to the site of zona photoablation. This dye is only passed onto daughter blastomeres and therefore allows study of specific cell lines. Embryonic growth was assessed following cell separation at the morula and blastocyst stage. Four-cell embryos treated with the laser had significantly fewer cells 12 h after zona photoablation than control embryos. A similar effect was noted after 24 h between dye injected embryos and those injected and lased simultaneously, indicating potential toxic effects of the laser treatment on the embryo. Effects on the blastomere closest to the site of ablation were evaluated by calculating the ratio of dyed cells to the total number of cells at specific time intervals. The ratios were similar in the dye and laser + dye groups of treated 4-cell embryos 36 h after treatment (0.22 and 0.23, respectively), indicating that the dye was still present in approximately 25% of the cells and that the negative effect of photoablation was evenly distributed among the blastomeres. It is concluded that zona photoablation may have long-term detrimental effects of a non-topical nature on precompacted mouse embryos in spite of the apparent precision of the laser spot size.
Evaluation of the antifertility activity of the broomSpartium junceumin the mammalian male
Authors: Baccetti B. , Burrini A.G. , Chen J.S. , Collodel G. , Giachetti D. , Matteucci F. , Menesini-Chen M.G. , Moretti E. , Piomboni P. , Sensini C. 
Published: September 2008

SummaryMale adult rabbits and rats treated withSpartium junceumshowed a significant decrease in fertility, demonstrated by a lower number of pregnancies. The target of the drug seems to be the acrosomal protease system, the activity of which appears greatly reduced, while the morphology of testicular cells and epididymal spermatozoa is only partially affected. The antifertility effect is completely reversible.