532 research outputs found
Modelling flow through a permeable bed: a combined physical-numerical approach
River hydrodynamicsTurbulent open channel flow and transport phenomen
Advancing the Understanding of Environmental Transformations, Bioavailability and Effects of Nanomaterials, an International US Environmental Protection AgencyâUK Environmental Nanoscience Initiative Joint Program.
Nanotechnology has significant economic, health, and environmental benefits, including renewable energy and innovative environmental solutions. Manufactured nanoparticles have been incorporated into new materials and products because of their novel or enhanced properties. These very same properties also have prompted concerns about the potential environmental and human health hazard and risk posed by the manufactured nanomaterials. Appropriate risk management responses require the development of models capable of predicting the environmental and human health effects of the nanomaterials. Development of predictive models has been hampered by a lack of information concerning the environmental fate, behavior and effects of manufactured nanoparticles. The United Kingdom (UK) Environmental Nanoscience Initiative and the United States (US) Environmental Protection Agency have developed an international research program to enhance the knowledgebase and develop risk-predicting models for manufactured nanoparticles. Here we report selected highlights of the program as it sought to maximize the complementary strengths of the transatlantic scientific communities by funding three integrated US-UK consortia to investigate the transformation of these nanoparticles in terrestrial, aquatic, and atmospheric environment. Research results demonstrate there is a functional relationship between the physicochemical properties of environmentally transformed nanomaterials and their effects and that this relationship is amenable to modeling. In addition, the joint transatlantic program has allowed the leveraging of additional funding, promoting transboundary scientific collaboration
IFITM3 restricts the morbidity and mortality associated with influenza
The 2009 H1N1 influenza pandemic showed the speed with which a novel respiratory virus can spread and the ability of a generally mild infection to induce severe morbidity and mortality in a subset of the population. Recent in vitro studies show that the interferon-inducible transmembrane (IFITM) protein family members potently restrict the replication of multiple pathogenic viruses1, 2, 3, 4, 5, 6, 7. Both the magnitude and breadth of the IFITM proteinsâ in vitro effects suggest that they are critical for intrinsic resistance to such viruses, including influenza viruses. Using a knockout mouse model8, we now test this hypothesis directly and find that IFITM3 is essential for defending the host against influenza A virus in vivo. Mice lacking Ifitm3 display fulminant viral pneumonia when challenged with a normally low-pathogenicity influenza virus, mirroring the destruction inflicted by the highly pathogenic 1918 âSpanishâ influenza9, 10. Similar increased viral replication is seen in vitro, with protection rescued by the re-introduction of Ifitm3. To test the role of IFITM3 in human influenza virus infection, we assessed the IFITM3 alleles of individuals hospitalized with seasonal or pandemic influenza H1N1/09 viruses. We find that a statistically significant number of hospitalized subjects show enrichment for a minor IFITM3 allele (SNP rs12252-C) that alters a splice acceptor site, and functional assays show the minor CC genotype IFITM3 has reduced influenza virus restriction in vitro. Together these data reveal that the action of a single intrinsic immune effector, IFITM3, profoundly alters the course of influenza virus infection in mouse and human
The effect of professional development on elementary science teachersâ understanding, confidence, and classroom implementation of reformâbased science instruction
Through a randomized controlled trial, this mixedâmethods study evaluated changes in elementary science teachersâ understandings, confidence, and classroom implementation of problemâbased learning (PBL), inquiry, and nature of science (NOS) instruction following participation in a professional development (PD) as well as the components of the PD that teachers perceived facilitated these changes. Results indicated that following the PD, treatment teacher (nâ=â139) understandings of and confidence for teaching inquiry, NOS, and PBL were significantly greater than control teachers (nâ=â98) after controlling for preunderstandings and confidence. The effect sizes were large. Treatment teachers also incorporated significantly more PBL, inquiry, and NOS into their instruction. Modeling, microteaching with feedback and reflection, and inâclassroom coaching facilitated teachersâ confidence, understanding, and intention to implement the reformâbased practices they learned. Implications for the understanding of the relationship between knowledge, confidence, and practice as well as elementary science teacher PD design are discussed
Epistemological framing and novice elementary teachersâ approaches to learning and teaching engineering design
As engineering learning experiences increasingly begin in elementary school, elementary teacher preparation programs are an important site for the study of teacher development in engineering education. In this article, we argue that the stances that novice teachers adopt toward engineering learning and knowledge are consequential for the opportunities they create for students. We present a comparative case study examining the epistemological framing dynamics of two novice urban teachers, Ana and Ben, as they learned and taught engineering design during a fourâweek institute for new elementary teachers. Although the two teachers had very similar teacher preparation backgrounds, they interpreted the purposes of engineering design learning and teaching in meaningfully different ways. During her own engineering sessions, Ana took up the goal not only of meeting the needs of the client but also of making scientific sense of artifacts that might meet those needs. When facilitating studentsâ engineering, she prioritized their building knowledge collaboratively about how things work. By contrast, when Ben worked on his own engineering, he took up the goal of delivering a product. When teaching engineering to students, he offered them constrained prototyping tasks to serve as handsâon contexts for reviewing scientific explanations. These findings call for teacher educators to support teachersâ framing of engineering design as a knowledge building enterprise through explicit conversations about epistemology, apprenticeship in senseâmaking strategies, and tasks intentionally designed to encourage reasoning about design artifacts.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151339/1/tea21541_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151339/2/tea21541.pd
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