478 research outputs found

    Exploring Metacognition as a Support for Learning Transfer

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    The ability to transfer learning to new situations lies at the heart of lifelong learning and the employability of university graduates. Because students are often unaware of the importance of learning transfer and staff do not always explicitly articulate this expectation, this article explores the idea that metacognition (intentional awareness and the use of that awareness) might enhance the development of learning transfer. Our exploratory study includes results from a survey of 74 staff and 118 students from five institutions in Australia, Belgium, UK, and USA. Our data indicate that many staff and a majority of students do not have a clear understanding of what learning transfer entails, and that there are many mismatches between staff and student perceptions, attitudes, and behaviors regarding learning transfer. This helps explain why learning transfer does not occur as often as it could. We found significant positive correlations between thinking about transfer and thinking about learning processes and the likelihood to use awareness to guide practice. These support the idea that metacognition might enhance learning transfer. We offer suggestions for future scholarship of teaching and learning

    Gravel pits support waterbird diversity in an urban landscape

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    We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space

    Molecular Detection of Invasive Species in Heterogeneous Mixtures Using a Microfluidic Carbon Nanotube Platform

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    Screening methods to prevent introductions of invasive species are critical for the protection of environmental and economic benefits provided by native species and uninvaded ecosystems. Coastal ecosystems worldwide remain vulnerable to damage from aquatic species introductions, particularly via ballast water discharge from ships. Because current ballast management practices are not completely effective, rapid and sensitive screening methods are needed for on-site testing of ships in transit. Here, we describe a detection technology based on a microfluidic chip containing DNA oligonucleotide functionalized carbon nanotubes. We demonstrate the efficacy of the chip using three ballast-transported species either established (Dreissena bugensis) or of potential threat (Eriocheir sinensis and Limnoperna fortuneii) to the Laurentian Great Lakes. With further refinement for on-board application, the technology could lead to real-time ballast water screening to improve ship-specific management and control decisions

    Stage-Specific Pathways of Leishmania infantum chagasi Entry and Phagosome Maturation in Macrophages

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    The life stages of Leishmania spp. include the infectious promastigote and the replicative intracellular amastigote. Each stage is phagocytosed by macrophages during the parasite life cycle. We previously showed that caveolae, a subset of cholesterol-rich membrane lipid rafts, facilitate uptake and intracellular survival of virulent promastigotes by macrophages, at least in part, by delaying parasitophorous vacuole (PV)-lysosome fusion. We hypothesized that amastigotes and promastigotes would differ in their route of macrophage entry and mechanism of PV maturation. Indeed, transient disruption of macrophage lipid rafts decreased the entry of promastigotes, but not amastigotes, into macrophages (P<0.001). Promastigote-containing PVs were positive for caveolin-1, and co-localized transiently with EEA-1 and Rab5 at 5 minutes. Amastigote-generated PVs lacked caveolin-1 but retained Rab5 and EEA-1 for at least 30 minutes or 2 hours, respectively. Coinciding with their conversion into amastigotes, the number of promastigote PVs positive for LAMP-1 increased from 20% at 1 hour, to 46% by 24 hours, (P<0.001, Chi square). In contrast, more than 80% of amastigote-initiated PVs were LAMP-1+ at both 1 and 24 hours. Furthermore, lipid raft disruption increased LAMP-1 recruitment to promastigote, but not to amastigote-containing compartments. Overall, our data showed that promastigotes enter macrophages through cholesterol-rich domains like caveolae to delay fusion with lysosomes. In contrast, amastigotes enter through a non-caveolae pathway, and their PVs rapidly fuse with late endosomes but prolong their association with early endosome markers. These results suggest a model in which promastigotes and amastigotes use different mechanisms to enter macrophages, modulate the kinetics of phagosome maturation, and facilitate their intracellular survival

    Fulvestrant-induced expression of ErbB3 and ErbB4 receptors sensitizes oestrogen receptor-positive breast cancer cells to heregulin β1

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    Introduction We have previously reported that induction of epidermal growth factor receptor and ErbB2 in response to antihormonal agents may provide an early mechanism to allow breast cancer cells to evade the growth-inhibitory action of such therapies and ultimately drive resistant cell growth. More recently, the other two members of the ErbB receptor family, ErbB3 and ErbB4, have been implicated in antihormone resistance in breast cancer. In the present study, we have investigated whether induction of ErbB3 and/or ErbB4 may provide an alternative resistance mechanism to antihormonal action in a panel of four oestrogen receptor (ER)-positive breast cancer cell lines. Methods MCF-7, T47D, BT474 and MDAMB361 cell lines were exposed to fulvestrant (100 nM) for seven days, and effects on ErbB3/4 expression and signalling, as well as on cell growth, were assessed. Effects of heregulin β1 (HRGβ1) were also examined in the absence and presence of fulvestrant to determine the impact of ER blockade on the capacity of this ErbB3/4 ligand to promote signalling and cell proliferation. Results Fulvestrant potently reduced ER expression and transcriptional activity and significantly inhibited growth in MCF-7, T47D, BT474 and MDAMB361 cells. However, alongside this inhibitory activity, fulvestrant also consistently induced protein expression and activity of ErbB3 in MCF-7 and T47D cells and ErbB4 in BT474 and MDAMB361 cell lines. Consequently, fulvestrant treatment sensitised all cell lines to the actions of the ErbB3/4 ligand HRGβ1 with enhanced ErbB3/4-driven signalling activity, reexpression of cyclin D1 and significant increases in cell proliferation being observed when compared to untreated cells. Indeed, in T47D and MDAMB361 HRGβ1 was converted from a ligand having negligible or suppressive growth activity into one that potently promoted cell proliferation. Consequently, fulvestrant-mediated growth inhibition was completely overridden by HRGβ1 in all four cell lines. Conclusions These findings suggest that although antihormones such as fulvestrant may have potent acute growth-inhibitory activity in ER-positive breast cancer cells, their ability to induce and sensitise cells to growth factors may serve to reduce and ultimately limit their inhibitory activity

    Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi

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    DNA phylogenetic comparisons have shown that morphology-based species recognition often underestimates fungal diversity. Therefore, the need for accurate DNA sequence data, tied to both correct taxonomic names and clearly annotated specimen data, has never been greater. Furthermore, the growing number of molecular ecology and microbiome projects using high-throughput sequencing require fast and effective methods for en masse species assignments. In this article, we focus on selecting and re-annotating a set of marker reference sequences that represent each currently accepted order of Fungi. The particular focus is on sequences from the internal transcribed spacer region in the nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Re-annotated and verified sequences were deposited in a curated public database at the National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci (RTL) database, and will be visible during routine sequence similarity searches with NR_prefixed accession numbers. A set of standards and protocols is proposed to improve the data quality of new sequences, and we suggest how type and other reference sequences can be used to improve identification of Fungi

    The trophic importance of epiphytic algae in a freshwater macrophyte system (Potamogeton perfoliatus L.): stable isotope and fatty acid analyses

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    Stable isotope and fatty acid analyses were used to study carbon sources for animals in a submerged plant bed. Epiphytes growing on Potamogeton perfoliatus, sand microflora, and alder leaves were the most important carbon sources. The most abundant macrophyte, P. perfoliatus was unimportant as a food source. Modelling (IsoSource) showed that epiphytes were the most important food source for the most abundant benthic invertebrates, the isopod Asellus aquaticus (annual mean contribution 64%), the amphipod Gammarus pulex (66%), and the gastropod Potamopyrgus antipodarum (83%). The mean annual contributions of sand microflora were, respectively, 21, 19, and 9%; and of alder leaves, 15, 15, and 8% for these three species. The relative importance of carbon sources varied seasonally. The relative contribution of epiphytes was lowest for all three grazer species in July: A. aquaticus 38%, G. pulex 43%, and P. antipodarum 42%. A decline in epiphyte biomass in summer may have caused this switch to less attractive food sources. P. perfoliatus provided habitat and shelter for consumers, but food was mainly supplied indirectly by providing space for attached epiphytes, which are fast-growing and provide a highly nutritious food source

    Similarities and Differences in Chinese and Caucasian Adults' Use of Facial Cues for Trustworthiness Judgments

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    All cultural groups in the world place paramount value on interpersonal trust. Existing research suggests that although accurate judgments of another's trustworthiness require extensive interactions with the person, we often make trustworthiness judgments based on facial cues on the first encounter. However, little is known about what facial cues are used for such judgments and what the bases are on which individuals make their trustworthiness judgments.In the present study, we tested the hypothesis that individuals may use facial attractiveness cues as a “shortcut” for judging another's trustworthiness due to the lack of other more informative and in-depth information about trustworthiness. Using data-driven statistical models of 3D Caucasian faces, we compared facial cues used for judging the trustworthiness of Caucasian faces by Caucasian participants who were highly experienced with Caucasian faces, and the facial cues used by Chinese participants who were unfamiliar with Caucasian faces. We found that Chinese and Caucasian participants used similar facial cues to judge trustworthiness. Also, both Chinese and Caucasian participants used almost identical facial cues for judging trustworthiness and attractiveness.The results suggest that without opportunities to interact with another person extensively, we use the less racially specific and more universal attractiveness cues as a “shortcut” for trustworthiness judgments
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