1,523 research outputs found

    Animating Talk and Texts: Culturally Relevant Teacher Read-Alouds of Informational Texts

    Get PDF
    This article describes the classroom interactions surrounding teacher read-alouds of nonfiction texts in the classroom of a teacher who strived for cultural relevancy. Participants in this study were one European American teacher and her upper- elementary students who lived in the surrounding working-class neighborhood; all but two students identified as Latino or African American. Data were collected for two consecutive school years using ethnographic and discourse analytic methods. Analyses showed that the teacher took up three social positions (i.e., cultural advocate, facilitator of classroom interactions, and teacher of reading) by animating texts and students

    Situating Strategies: An Examination of Comprehension Strategy Instruction in One Upper Elementary Classroom Oriented Toward Culturally Relevant Teaching

    Get PDF
    Drawing on ethnographic and discourse analytic methods, this article examines how comprehension strategies aligned with goals in a classroom oriented toward culturally relevant teaching. Findings indicate that (a) two distinct sets of comprehension were taught in the room and (b) one set aligned more easily with culturally relevant teaching than the other

    Beyond Heroes & Role Models: Using Biographies to Develop Young Change Agents

    Get PDF
    Reading, writing, and discussing biographies provide unique opportunities for teachers and students. Critical thinking can be developed through questioning, predicting, and analyzing various biographical mediums--texts, photographs and illustrations, book reviews, websites, films, news articles, etc.--to learn more about an individual\u27s life experiences and choices. Decision making skills can be enhanced when students juxtapose their perceptions of heroes and role models to that of a change agent, even considering how their own life experiences and choices may be contributing to larger actions of change. In this article, the authors discuss six biographies that could be used with young people in the elementary classroom to study change agents. The authors carefully selected and organized their literary choices into four categories: (1) familiar historical figures, (2) familiar living persons, (3) less familiar figures, and finally (4) students and teachers themselves--because they can act as change agents today on a local and personal level

    Shear-driven size segregation of granular materials: modeling and experiment

    Full text link
    Granular materials segregate by size under shear, and the ability to quantitatively predict the time required to achieve complete segregation is a key test of our understanding of the segregation process. In this paper, we apply the Gray-Thornton model of segregation (developed for linear shear profiles) to a granular flow with an exponential profile, and evaluate its ability to describe the observed segregation dynamics. Our experiment is conducted in an annular Couette cell with a moving lower boundary. The granular material is initially prepared in an unstable configuration with a layer of small particles above a layer of large particles. Under shear, the sample mixes and then re-segregates so that the large particles are located in the top half of the system in the final state. During this segregation process, we measure the velocity profile and use the resulting exponential fit as input parameters to the model. To make a direct comparison between the continuum model and the observed segregation dynamics, we locally map the measured height of the experimental sample (which indicates the degree of segregation) to the local packing density. We observe that the model successfully captures the presence of a fast mixing process and relatively slower re-segregation process, but the model predicts a finite re-segregation time, while in the experiment re-segregation occurs only exponentially in time

    Name Games: Literacy and Play in the Prekindergarten Classroom

    Get PDF
    Teachers and researchers have found that having writing materials in all play centers in early childhood classrooms makes it easy for children to experience and work with print as they play with names. Children’s interest in their own names can be used as a tool for increasing their awareness of and experiences with print awareness and writing

    Testosterone Trajectories and Reference Ranges in a Large Longitudinal Sample of Male Adolescents

    Get PDF
    Pubertal dynamics plays an important role in physical and psychological development of children and adolescents. We aim to provide reference ranges of plasma testosterone in a large longitudinal sample. Furthermore, we describe a measure of testosterone trajectories during adolescence that can be used in future investigations of development.We carried out longitudinal measurements of plasma testosterone in 2,216 samples obtained from 513 males (9 to 17 years of age) from the Avon Longitudinal Study of Parents and Children. We used integration of a model fitted to each participant's testosterone trajectory to calculate a measure of average exposure to testosterone over adolescence. We pooled these data with corresponding values reported in the literature to provide a reference range of testosterone levels in males between the ages of 6 and 19 years.The average values of total testosterone in the ALSPAC sample range from 0.82 nmol/L (Standard Deviation [SD]: 0.09) at 9 years of age to 16.5 (SD: 2.65) nmol/L at 17 years of age; these values are congruent with other reports in the literature. The average exposure to testosterone is associated with different features of testosterone trajectories such as Peak Testosterone Change, Age at Peak Testosterone Change, and Testosterone at 17 years of age as well as the timing of the growth spurt during puberty.The average exposure to testosterone is a useful measure for future investigations using testosterone trajectories to examine pubertal dynamics

    Scaffolding Classroom Discourse in an Election Year: Keeping a Cool Mood in a Heated Season

    Get PDF
    Certainly, teaching about politics can be daunting, especially as the political climate in the United States becomes increasingly partisan as a result of heated political rhetoric amplified through a variety of media outlets. However, elementary teachers can help students develop the respectful dispositions they will need as young adults living in an increasingly pluralistic society. These dispositions can be fostered only if teachers are willing to engage their young learners in discussions of politics as part of the curriculum. In this article, the authors discuss ways in which teachers can promote political tolerance and respect during coverage of a presidential election, a high-profile event that social studies educators Mary Haas and Margaret Laughlin describe as the quintessential example of teaching social studies. Here, the authors also describe instructional strategies designed specifically for the upper elementary grades, although they note ways in which teachers can adapt these strategies for younger learners as well

    Divergence between genes but limited allelic polymorphism in two MHC class II A genes in Leach’s storm-petrels Oceanodroma leucorhoa

    Get PDF
    The major histocompatibility complex (MHC) is critical to host-pathogen interactions. Class II MHC is a heterodimer, with α and β subunits encoded by different genes. The peptide-binding groove is formed by the first domain of both subunits (α1 and β1), but studies of class II variation or natural selection focus primarily on the β subunit and II B genes. We explored MHC II A in Leach’s storm-petrel, a seabird with two expressed, polymorphic II B genes. We found two II A genes, Ocle-DAA and Ocle-DBA, in contrast to the single II A gene in chicken and duck. In exon 2 which encodes the α1 domain, the storm-petrel II A genes differed strongly from each other but showed little within-gene polymorphism in 30 individuals: just one Ocle-DAA allele, and three Ocle-DBA alleles differing from each other by single non-synonymous substitutions. In a comparable sample, the two II B genes had nine markedly diverged alleles each. Differences between the α1 domains of Ocle-DAA and Ocle-DBA showed signatures of positive selection, but mainly at non-peptide-binding site (PBS) positions. In contrast, positive selection within and between the II B genes corresponded to putative PBS codons. Phylogenetic analysis of the conserved α2 domain did not reveal deep or well-supported lineages of II A genes in birds, in contrast to the pronounced differentiation of DQA, DPA, and DRA isotypes in mammals. This uncertain homology complicates efforts to compare levels of functional variation and modes of evolution of II A genes across taxa

    Bioinformatic characterisation of the effector repertoire of the strawberry pathogen Phytophthora cactorum

    Get PDF
    The oomycete pathogen Phytophthora cactorum causes crown rot, a major disease of cultivated strawberry. We report the draft genome of P. cactorum isolate 10300, isolated from symptomatic Fragaria x ananassa tissue. Our analysis revealed that there are a large number of genes encoding putative secreted effectors in the genome, including nearly 200 RxLR domain containing effectors, 77 Crinklers (CRN) grouped into 38 families, and numerous apoplastic effectors, such as phytotoxins (PcF proteins) and necrosis inducing proteins. As in other Phytophthora species, the genomic environment of many RxLR and CRN genes differed from core eukaryotic genes, a hallmark of the two-speed genome. We found genes homologous to known Phytophthora infestans avirulence genes including Avr1, Avr3b, Avr4, Avrblb1 and AvrSmira2 indicating effector sequence conservation between Phytophthora species of clade 1a and clade 1c. The reported P. cactorum genome sequence and associated annotations represent a comprehensive resource for avirulence gene discovery in other Phytophthora species from clade 1 and, will facilitate effector informed breeding strategies in other crops
    • …
    corecore