9 research outputs found
Oral Narrative Genres as Dialogic Resources for Classroom Literature Study: A Contextualized Case Study of Conversational Narrative Discussion
Five questions guided a case study exploring the relationship between oral narrative and discussion in middle school literature study: (a) Relative to similar classrooms in a large-scale study, how can overall literature instruction be characterized? (b) Relative to similar classrooms in a large-scale study, how well do students achieve in the focal classroom? (c) What, if any, are the links between oral narrative and discussion? (d) If discussion and narrative co-occur, what sorts of oral narratives do narrators tell in discussions? and (e) If discussion and narrative co-occur, how can we characterize the overlap in terms of interaction? In the frequent conversational narrative discussions, where oral narrative and discussion discourse overlapped, teacher and students used various kinds of oral narrative genres to prime, sustain, ratify, and amplify discussion
Ceratocystis species, including two new taxa, from Eucalyptus trees in South Africa
The ascomycete genus Ceratocystis (Microascales, Ceratocystidaceae) includes important fungal
pathogens of trees, including Eucalyptus species. Ceratocystis species and their Thielaviopsis asexual
states are typically associated with insects, such as nitidulid beetles, that spread them over long distances.
Eucalyptus trees comprise a substantial component of the forestry industry in South Africa, however,
limited information is available regarding Ceratocystis species that infect these trees. In this study,
Ceratocystis species were collected from wounds on Eucalyptus trees in all the major plantation regions
of South Africa, as well as from insects associated with these wounds. Both morphology and multigene
DNA sequence analyses, using three nuclear loci, were used to identify the Ceratocystis species. Of the
260 isolates collected, nine Ceratocystis species, of which two were represented only by their
Thielaviopsis anamorph states were identified. These species were C. eucalypticola, C. pirilliformis, C.
savannae, C. oblonga, C. moniliformis, T. basicola, T. thielavioides and two Ceratocystis species that are
described here as C. salinaria sp. nov. and C. decipiens sp. nov. Insects associated with these
Ceratocystis species were Brachypeplus depressus (Nitidulidae), Carpophylus bisignatus, C. dimidiatus
(Nitidulidae), Xyleborus affinis (Scolytidae), Litargus sp. (Mycetophagidae) and a Staphylinid
(Staphylinidae) species.National Research Foundation of South Africa (NRF), the THRIP Initiative of the Department of Trade and Industry (THRIP/DST), members of the Tree Protection Cooperative Programme (TPCP) and the University of Pretoria.http://link.springer.com/journal/13313hb201
Ophiostomatoid fungi associated with mangroves in South Africa, including Ophiostoma palustre sp. nov.
Mangrove trees are continuously under stress due to environmental and/or anthropogenic pressures, which expose them to attack by pathogens, compromising their survival. Ophiostomatoid fungi cause sap stain and diseases of a wide spectrum of tree species globally. These fungi infect trees through natural, insect, animal and/or human made wounds. During routine surveys of mangrove trees in South Africa, wounds on branches and stems of Avicennia marina were regularly monitored for the presence of ophiostomatoid fungi at ten study sites in the country. The stems of four mangrove species, A. marina, Bruguiera gymnorrhiza, Rhizophora mucronata and Barringtonia racemosa were also wounded and evaluated for the appearance of these fungi. Ophiostomatoid fungi were obtained from the mangrove associate B. racemosa, but not from any of the true mangroves. Analyses of DNA sequence data for the internal transcribed spacer, β-tubulin, calmodulin and translation elongation factor gene regions revealed that the fungi isolated from the wounds on B. racemosa belong to three species in the Ophiostomataceae, including a new taxon described here as Ophiostoma palustre sp. nov. These results suggest that the mangrove associate B. racemosa is more prone to colonization by ophiostomatoid fungi than the true mangroves.The Department of Science and Technology (DST) and National Research Foundation (NRF) Center of Excellence in Tree Health Biotechnology (CTHB).http://link.springer.com/journal/104822017-12-30Microbiology and Plant PathologyForestry and Agricultural Biotechnology Institute (FABI)Plant Production and Soil Scienc
Writing proficiency level and writing development of low-achieving adolescents: the roles of linguistic knowledge, fluency, and metacognitive knowledge
In a longitudinal design, 51 low-achieving adolescents' development in writing proficiency from Grades 7 to 9 was measured. There were 25 native-Dutch and 26 language-minority students. In addition, the roles of (i) linguistic knowledge, (ii) metacognitive knowledge, and (iii) linguistic fluency in predicting both the level and development of writing proficiency were assessed. Low-achieving students improved in writing proficiency, the language-minority students more so than the native-Dutch students. Regarding the level of writing proficiency, individual differences between low-achieving adolescents could be accounted for by receptive vocabulary, grammatical knowledge, and speed of sentence verification, suggesting that these are important components in low-achieving adolescents' writing. Regarding development in writing proficiency, grammatical knowledge predicted variation between lowachieving students. Explanations and educational implications of these findings are discussed