64 research outputs found

    The synthesis and characterization of some new difluorophosphine derivatives

    Full text link
    The heretofore unknown chelating fluorophosphine ligands, F2PCH2PF2 and F2PCH2CH=CH2 have been prepared and characterized. The reagent F2PCH2I has been prepared and used in the synthesis of F2PCH2PF2. NMR data are given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21864/1/0000268.pd

    TRY plant trait database – enhanced coverage and open access

    Get PDF
    Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Opportunities and challenges of China’s inquiry-based education reform in middle and high schools: Perspectives of science teachers and teacher educators

    Full text link
    Consistent with international trends, an emergent interest in inquiry-based science teaching and learning in K-12 schools is also occurring in China. This study investigates the possibilities for and the barriers to enactment of inquiry-based science education in Chinese schools. Altogether 220 Chinese science teachers, science teacher educators and researchers (primarily from the field of chemistry education) participated in this study in August 2001. Participants represented 13 cities and provinces in China. We administered two questionnaires, one preceding and one following a 3-hour presentation by a US science educator and researcher about inquiry-based teaching and learning theories and practices. In each of three sites in which the study was conducted (Shanghai, Guangzhou and Beijing), questionnaires were administered, and four representative participants were interviewed. Our coding and analysis of quantifiable questionnaire responses (using a Likert scale), of open-ended responses, and of interview transcripts revealed enthusiastic interest in incorporating inquiry-based teaching and learning approaches in Chinese schools. However, Chinese educators face several challenges: (a) the national college entrance exam needs to align with the goals of inquiry-based teaching; (b) systemic reform needs to happen in order for inquiry-based science to be beneficial to students, including a change in the curriculum, curriculum materials, relevant resources, and teacher professional development; (c) class size needs to be reduced; and (d) an equitable distribution of resources in urban and rural schools needs to occur.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42933/1/10763_2005_Article_1517.pd
    • 

    corecore