Increasing atmospheric carbon dioxide is responsible for climate changes that are having widespread effects on biological systems. One of the clearest changes is earlier onset of spring and lengthening of the growing season. We designed the present study to examine the interactive effects of timing of dormancy release of seeds with low and high atmospheric CO2 on biomass, reproduction, and phenology in ragweed plants (Ambrosia artemisiifolia L.), which produce highly allergenic pollen. We released ragweed seeds from dormancy at three 15-day intervals and grew plants in climate-controlled glasshouses at either ambient or 700-ppm CO2 concentrations, placing open-top bags over inflorescences to capture pollen. Measurements of plant height and weight; inflorescence number, weight, and length; and days to anthesis and anthesis date were made on each plant, and whole-plant pollen productivity was estimated from an allometric-based model. Timing and CO2 interacted to influence pollen production. At ambient CO2 levels, the earlier cohort acquired a greater biomass, a higher average weight per inflorescence, and a larger number of inflorescences; flowered earlier; and had 54.8% greater pollen production than did the latest cohort. At high CO2 levels, plants showed greater biomass and reproductive effort compared with those in ambient CO2 but only for later cohorts. In the early cohort, pollen production was similar under ambient and high CO2, but in the middle and late cohorts, high CO2 increased pollen production by 32% and 55%, respectively, compared with ambient CO2 levels. Overall, ragweed pollen production can be expected to increase significantly under predicted future climate conditions.

This study explores the interplay between early reading, identity and bilingualism. Reading identities, or understandings about what reading is and whom one is as a reader, have been linked to reading achievement and the development of reading skills. Only a small portion of the overall research on reading identities has included dual language learners. This exploratory study provides a description of the reading identities of three dual language learners in prekindergarten. Data include child-centered interviews, child and classroom observations, teacher interviews and a family questionnaire. Methods centered on the use of child-oriented data collection protocols, and the inclusion of children in the interpretation of their own work and language. Through the exploration of three cases, this study documents the ways that reading identities were constructed, taken up and expressed by the participants. This study provides evidence that dual language learners are actively constructing ideas about reading, bilingualism/biliteracy, and whom they are as readers as they learn to read. These findings show that framing early reading in an identity perspective presents opportunities to look more holistically at the language and reading practices of dual language learners as they learn to read and navigate two or more languages at home and school.

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Education researchers have extensively studied classroom discourse as a way to understand classroom structures and learning. This article proposes the use of social network analysis (SNA) as a method for discourse studies in education. SNA enables us to learn about the connections between persons and the patterns of relations within groups. This presents a novel approach to the study of discourse that may more accurately reflect current understandings of discourse as a social phenomenon. This article explains the theoretical links between SNA and the concept of discourse in education and then considers how SNA can be used to examine classroom discourse. A brief overview of promising methods is presented to provide examples of how SNA can be applied to discourse data. This article argues that continued exploration and applications of SNA could yield more complex understandings of the role of discourse in learning opportunities and outcomes.

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