Teacher knowledge for modelling and problem solving

This article reports on a study that has researched teacher professional learning in lesson study communities that enquired into how we might better support students develop skills in problem solving and mathematical modelling. A rationale for professional development of this type, both in in terms of its structure and focus, is presented followed by an illustrative description from the study of a typical research lesson and issues raised in the post-lesson discussion. This is used to provide insight into some of the key issues to consider in developing teacher knowledge for modelling and problem solving

Professional learning through the collaborative design of problem-solving lessons

This paper analyses lesson study as a mode of professional learning, focused on the development of mathematical problem solving processes, using the lens of Cultural-Historical Activity Theory. In particular we draw attention to two activity systems, the classroom system and the lesson-study system, and the importance of making artefacts instrumental in both. We conceptualise the lesson plan as a boundary object and use this to illustrate how professional learning takes place through the introduction of carefully designed artefacts that draw on teachers’ professional knowledge of potential student approaches, and to the nature of progression in problem-solving processes. We identify the roles of instrumentalisation and instrumentation in supporting professional learning as these artefacts are prepared for use before a lesson and as they are again used as catalysts for reflection in post-lesson discussions. These artefacts are seen to effectively facilitate the socially-situated learning of all participants. We conclude that the design of artefacts as boundary objects that support teaching and professional learning in their respective activity systems may be fundamental to the success of lesson study as a collaborative venture

Lelliottia amnigena recovered from the lung of a harbour porpoise, and comparative analyses with Lelliottia spp

Strain M1325/93/1 (herein referred to by our laboratory identifier, GFKo1) of Lelliottia amnigena was isolated from the lung of a harbour porpoise in 1993. The genome sequence and antimicrobial resistance profile (genomic, phenotypic) of the strain were generated, with the genomic data compared with those from closely related bacteria. We demonstrate that the recently described chromosomally encoded AmpC β-lactamase bla LAQ is a core gene of L. amnigena , and suggest that new variants of this class of lactamase are encoded by other members of the genus Lelliottia . Although presence of bla LAQ is ubiquitous across the currently sequenced members of L. amnigena , we highlight that strain GFKo1 is sensitive to ampicillin and cephalosporins. These data suggest that bla LAQ may act as a useful genetic marker for identification of L. amnigena strains, but its presence may not correlate with expected phenotypic resistances. Further studies are required to determine the regulatory mechanisms of bla LAQ in L. amnigena

The Parthenon, April 17, 2015

The Parthenon, Marshall University’s student newspaper, is published by students Monday through Friday during the regular semester and weekly Thursday during the summer. The editorial staff is responsible for the news and the editorial content

The Parthenon, February 6, 2015

The Parthenon, Marshall University’s student newspaper, is published by students Monday through Friday during the regular semester and weekly Thursday during the summer. The editorial staff is responsible for the news and the editorial content

The Parthenon, April 3, 2015

The Parthenon, Marshall University’s student newspaper, is published by students Monday through Friday during the regular semester and weekly Thursday during the summer. The editorial staff is responsible for the news and the editorial content

Macro scale physical model of nanoindentation on vertically aligned carbon nanotube forests

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 55-56).Currently the process of nanoindentation is being explored as a reliable means of determining the mechanical properties of carbon nanotubes (CNTs) and the constituent tubes of vertically aligned carbon nanotube (VACNT) forests. Under indentation, each CNT can be modeled as a cantilevered beam subjected to deflection from the penetration of the indenter. The resistance to indentation is the result of the cumulative bending of the VACNTs. Using beam theory, the effective bending stiffness is determined by fitting the mechanical model to the indentation force-penetration curves. In order to validate the process of nanoindentation as a means of determining the elastic modulus of CNTs, a macro scale physical model was built using cylindrical rods of a known material and used to help explain some of the interactions of the tubes and indenter. Two models and two indenters were built to explore these effects and how they changed between models and indenters. The models demonstrated that for the indenter with a low face angle, the process was rather accurate with corresponding errors of 7% and 15%. When using a flatter indenter on both models, particularly the model with the higher areal density of tubes, demonstrated the inaccuracy of the process as a means for determining the elastic modulus of the material. Such a result was due to abnormal spikes in the data that were observable and attributed to tube interaction with the edge of the indenter. The process of indentation is reliable when the aberrations are minimal or are identifiable in the indentation force versus indentation depth curves and thus can be easily discounted. The process of scratching was also explored. For scratching the indenter is fixed at a certain indentation height and the tube forest(cont.) is then horizontally displaced and thus further deflects the tubes. The tubes enter three phases of contact, which subsequently affect the behavior of the scratching force versus distance curves. The macro scale model was used to validate the predicted behavior of CNTs. In general the scratching data supported the behavior of a three phase interaction between the tubes and indenter and the subsequent curves. For more accurate results and numerical comparisons, the forests need to be displaced using a constant speed linear stage and measured against distance.by Geoffrey F. Ebeling.S.B

Single dissociative diffraction of protons in s\sqrt {s} = 8 TeV collisions with the ATLAS experiment

The first LHC-energy differential cross-sections of the single dissociative diffraction process $_{pp}$ $\rightarrow$ $X_p$ are presented as a function of Mandelstam-$t$, fractional proton energy loss $\xi$ and rapidity gaps within the ATLAS inner detector with a coverage of |$\eta$|< 2.5. The measurement is performed using a data sample collected with the ATLAS detector during a dedicated low luminosity run in 2012 with an integrated luminosity of 1.67 nb$^{-1}$ and a centre-of-mass energy of 8TeV. Events are triggered and selected using the ALFA forward detectors, in combination with the ATLAS central detector components, enabling the detection of scattered protons. The fiducial region is chosen to be 0.016 < |$t$| < 0.43 GeV$^2$ and −4.0 < log$_{10} \xi$ < -1.6. The cross-sections within this region are fitted within an interpretation based on Regge theory. The measured $B$ slope within this region is $B$ = 7.60$\pm$0.31 GeV$^{-2}$. The $\xi$ dependence of the cross-section is consistent with that expected from soft Pomeron exchange. The total measured cross-section within the fiducial region is 1.59$\pm$0.13mb. The Pythia8 A3 Monte Carlo tune provides a very good description of the shape of the cross-sections but overestimates the integrated cross-section by approximately 60%