Biliteracy effects on phonological awareness, oral language proficiency and reading skills in Taiwanese Mandarin-English bilingual children

The present study examined the effect of learning to read a heritage language on Taiwanese Mandarin-English bilingual children’s Chinese and English phonological awareness, Chinese and English oral language proficiency, and English reading skills. Participants were 40 Taiwanese Mandarin-English bilingual children and 20 English monolingual children in the U.S. Based on their performance on a Chinese character reading test, the bilingual participants were divided into two groups: the Chinese Beginning Reader and Chinese Nonreader groups. A single child categorized as a Chinese Advanced Reader also participated. Children received phonological awareness tasks, produced oral narrative samples from a wordless picture book, and took standardized English reading subtests. The bilingual participants received measures in both English and Chinese, whereas English monolingual children received only English measures. Additional demographic information was collected from a language background survey filled out by parents. Results of two MANOVAs indicated that the Chinese Beginning Reader group outperformed the Chinese Nonreader and English Monolingual groups on some phonological awareness measures and the English nonword reading test. In an oral narrative production task in English, the English Monolingual group produced a greater total number of words (TNW) and more different words (NDW) than the Chinese Nonreader group. Multiple regression analyses were conducted to determine whether bilingual children’s Chinese character reading ability would still account for a unique amount of variance in certain outcome variables, independent of nonverbal IQ and other potential demographic or performance variables and to clarify the direction of causality for bilingual children’s performance in the three domains. These results suggested that learning to read in a heritage language directly or indirectly enhances bilingual children’s ability in phonological awareness and certain English reading skills. It also appears that greater oral language proficiency in Chinese promotes early reading in the heritage language. Advanced heritage reading may produce even larger gains. Practical implications of learning a heritage language in the U.S. are discussed.

Comparative genomic approaches for investigating evolution in the microbial and viral populations of the rumen

The rumen is home to a diverse population of microorganisms encompassing all three domains of life: Bacteria, Archaea, and Eukarya. Viruses have also been documented to be present in large numbers; however, little is currently known about their role in the dynamics of the rumen ecosystem. This research aimed to use a comparative genomics approach in order to assess the potential evolutionary mechanisms at work in the rumen environment. We proposed to do this by first assessing the diversity and potential for horizontal gene transfer (HGT) of multiple strains of the cellulolytic rumen bacterium, Ruminococcus flavefaciens, and then by conducting a survey of rumen viral metagenome (virome) and subsequent comparison of the virome and microbiome sequences to ascertain if there was genetic information shared between these populations. We hypothesize that the bacteriophages play an integral role in the community dynamics of the rumen, as well as driving the evolution of the rumen microbiome through HGT. In our analysis of the Ruminococcus flavefaciens genomes, there were several mobile elements and clustered regularly interspaced short palindromic repeat (CRISPR) sequences detected, both of which indicate interactions with bacteriophages. The rumen virome sequences revealed a great deal of diversity in the viral populations. Additionally, the microbial and viral populations appeared to be closely associated; the dominant viral types were those that infect the dominant microbial phyla. The correlation between the distribution of taxa in the microbiome and virome sequences as well as the presence of CRISPR loci in the R. flavefaciens genomes, suggested that there is a “kill-the-winner” community dynamic between the viral and microbial populations in the rumen. Additionally, upon comparison of the rumen microbiome and rumen virome sequences, we found that there are many sequence similarities between these populations indicating a potential for phage-mediated HGT. These results suggest that the phages represent a gene pool in the rumen that could potentially contain genes that are important for adaptation and survival in the rumen environment, as well as serving as a molecular ‘fingerprint’ of the rumen ecosystem.