Early vocabulary development in English, Mandarin, and Cantonese : a cross-linguistic study based on Childes

Early language development is an exciting topic in the field of child language acquisition. Only a limited amount of cross-linguistic studies has attempted to investigate the similarities and differences in child language development across different languages. In this thesis, I present a study based on English, Mandarin and Cantonese corpora extracted from the Child Language Data Exchange System (CHILDES, MacWhinney, 2000). I investigated the lexical compositions of certain lexical categories (nouns, verbs, and adjectives) in children and their caregivers’ vocabularies across eight different children age groups ranging from 13 to 60 months. ANOVA, frequency analysis, and cluster analysis were used to analyze the data. The development trajectories of lexical diversity and complexity of children’s speech were also analyzed by two novel techniques: Dmeasure and the Mean Length of Utterances. My research clearly shows that (1) in all the cultures, children’s early language development exhibits roughly similar patterns: an increasing diversity in lexicon and increasingly complicated speech patterns emerge as a function of time, and children’s vocabularies become more similar to those of their parents over time; and (2) culture variations in children’s linguistic input have strong influences on their language output, which is reflected in the noun vs. verb ratio and the varying percentages of nouns, verbs, and adjectives in the total words children are able to speak in the three cultures

Minimal wave speed of traveling wavefronts in delayed Belousov-Zhabotinskii model

This paper is concerned with the traveling wavefronts of Belousov-Zhabotinskii model with time delay. By constructing proper upper and lower solutions and applying the theory of asymptotic spreading, the minimal wave speed is obtained under the weaker condition than that in the known results. Moreover, the strict monotonicity of any monotone traveling wavefronts is also established

On nonsingularity of combinations of two group invertible matrices and two tripotent matrices

Let T(1) and T(2) be two n x n tripotent matrices and c(1), c(2) two nonzero complex numbers. We mainly study the nonsingularity of combinations T = c(1)T(1) + c(2)T(2) - c(3)T(1)T(2) of two tripotent matrices T(1) and T(2), and give some formulae for the inverse of c(1)T(1) + c(2)T(2) - c(3)T(1)T(2) under some conditions. Some of these results are given in terms of group invertible matrices. (C) 2011 Taylor & FrancisX. Liu was supported by the National Natural Science Foundation of China (11061005) and the Ministry of Education Science and Technology Key Project (210164). J. Benitez was supported by Spanish Project MTM2010-18539. The authors wish to thank the referee for his/her careful review and comments which improved the quality of this article.Liu, X.; Wu, S.; Benítez López, J. (2011). On nonsingularity of combinations of two group invertible matrices and two tripotent matrices. Linear and Multilinear Algebra. 59(12):1409-1417. https://doi.org/10.1080/03081087.2011.558843S140914175912Baksalary, J. K., & Baksalary, O. M. (2004). Nonsingularity of linear combinationsof idempotent matrices. Linear Algebra and its Applications, 388, 25-29. doi:10.1016/j.laa.2004.02.025Baksalary, J. K., Baksalary, O. M., & Özdemir, H. (2004). A note on linear combinations of commuting tripotent matrices. Linear Algebra and its Applications, 388, 45-51. doi:10.1016/j.laa.2004.01.011Benítez, J., Liu, X., & Zhu, T. (2010). Nonsingularity and group invertibility of linear combinations of twok-potent matrices. Linear and Multilinear Algebra, 58(8), 1023-1035. doi:10.1080/03081080903207932Benítez, J., & Thome, N. (2006). {k}-Group Periodic Matrices. SIAM Journal on Matrix Analysis and Applications, 28(1), 9-25. doi:10.1137/s0895479803437384Gross, J., & Trenkler, G. (2000). Nonsingularity of the Difference of Two Oblique Projectors. SIAM Journal on Matrix Analysis and Applications, 21(2), 390-395. doi:10.1137/s0895479897320277Koliha, J. ., Rakočević, V., & Straškraba, I. (2004). The difference and sum of projectors. Linear Algebra and its Applications, 388, 279-288. doi:10.1016/j.laa.2004.03.008Meyer, C. (2000). Matrix Analysis and Applied Linear Algebra. doi:10.1137/1.9780898719512M. Sarduvan and H. Özdemir,On nonsingularity of linear combinations of tripotent matrices, Acta Universitatis Apulensis 25 (2011), pp. 159–164Zuo, K. (2010). Nonsingularity of the difference and the sum of two idempotent matrices. Linear Algebra and its Applications, 433(2), 476-482. doi:10.1016/j.laa.2010.03.01

Genome-wide investigation and expression analysis of OSCA gene family in response to abiotic stress in alfalfa

Alfalfa is an excellent leguminous forage crop that is widely cultivated worldwide, but its yield and quality are often affected by drought and soil salinization. Hyperosmolality-gated calcium-permeable channel (OSCA) proteins are hyperosmotic calcium ion (Ca2+) receptors that play an essential role in regulating plant growth, development, and abiotic stress responses. However, no systematic analysis of the OSCA gene family has been conducted in alfalfa. In this study, a total of 14 OSCA genes were identified from the alfalfa genome and classified into three groups based on their sequence composition and phylogenetic relationships. Gene structure, conserved motifs and functional domain prediction showed that all MsOSCA genes had the same functional domain DUF221. Cis-acting element analysis showed that MsOSCA genes had many cis-regulatory elements in response to abiotic or biotic stresses and hormones. Tissue expression pattern analysis demonstrated that the MsOSCA genes had tissue-specific expression; for example, MsOSCA12 was only expressed in roots and leaves but not in stem and petiole tissues. Furthermore, RT–qPCR results indicated that the expression of MsOSCA genes was induced by abiotic stress (drought and salt) and hormones (JA, SA, and ABA). In particular, the expression levels of MsOSCA3, MsOSCA5, MsOSCA12 and MsOSCA13 were significantly increased under drought and salt stress, and MsOSCA7, MsOSCA10, MsOSCA12 and MsOSCA13 genes exhibited significant upregulation under plant hormone treatments, indicating that these genes play a positive role in drought, salt and hormone responses. Subcellular localization results showed that the MsOSCA3 protein was localized on the plasma membrane. This study provides a basis for understanding the biological information and further functional analysis of the MsOSCA gene family and provides candidate genes for stress resistance breeding in alfalfa

The Mitochondrial Fission Receptor MiD51 Requires ADP as a Cofactor

Mitochondrial fission requires recruitment of dynamin- related protein 1 (Drp1) to the mitochondrial surface and activation of its GTP-dependent scission function. The Drp1 receptors MiD49 and MiD51 recruit Drp1 to facilitate mitochondrial fission, but their mechanism of action is poorly understood. Using X-ray crystallography, we demonstrate that MiD51 contains a nucleotidyl transferase domain that binds ADP with high affinity. MiD51 recruits Drp1 via a surface loop that functions independently of ADP binding. However, in the absence of nucleotide binding, the recruited Drp1 cannot be activated for fission. Purified MiD51 strongly inhibits Drp1 assembly and GTP hydrolysis in the absence of ADP. Addition of ADP relieves this inhibition and promotes Drp1 assembly into spirals with enhanced GTP hydrolysis. Our results reveal ADP as an essential cofactor for MiD51 during mitochondrial fission

On the Mechanism of Solvents Catalyzed Structural Transformation in Metal Halide Perovskites

Metal halide perovskites show the capability of performing structural transformation, allowing the formation of functional heterostructures. Unfortunately, the elusive mechanism governing these transformations limits their technological application. Herein, the mechanism of 2D–3D structural transformation is unraveled as catalyzed by solvents. By combining a spatial-temporal cation interdiffusivity simulation with experimental findings, it is validated that, protic solvents foster the dissociation degree of formadinium iodide (FAI) via dynamic hydrogen bond, then the stronger hydrogen bond of phenylethylamine (PEA) cation with selected solvents compared to dissociated FA cation facilitates 2D–3D transformation from (PEA)2PbI4 to FAPbI3. It is discovered that, the energy barrier of PEA out-diffusion and the lateral transition barrier of inorganic slab are diminished. For 2D films the protic solvents catalyze grain centers (GCs) and grain boundaries (GBs) transforme into 3D phases and quasi-2D phases, respectively. While in the solvent-free case, GCs transform into 3D–2D heterostructures along the direction perpendicular to the substrate, and most GBs evolve into 3D phases. Finally, memristor devices fabricated using the transformed films uncover that, GBs composed of 3D phases are more prone to ion migration. This work elucidates the fundamental mechanism of structural transformation in metal halide perovskites, allowing their use to fabricate complex heterostructures.</p