Implementing Mobile Environments using Learning Objects: The Athabasca University Digital Reading Room

Paper presented at the IEEE WMTE 2005.This investigation determined some of the better strategies for delivering educational resources to mobile devices from the Digital Reading Room (DRR) and the Athabasca University(AU) library catalogue using AirPac, making recommendations on the implementation of Mlearning as part of the AU e-learning strategy. The primary research question addressed in this short paper is What are the limitations and difficulties in delivering course materials to mobile devices

NMR structural studies of mismatched DNA base pairs and their interaction with E. coli MutS protein

Escherichia coli MutS is a DNA binding repair protein (97 kDa, monomer) and its biological significance arises from its recognition of mismatches which occur as errors during DNA replication. Mismatches and mutagenic bases represent a fascinating and diverse range of shapes and sizes and it is not obvious how a single protein (MutS) can recognise such molecular diversity against a huge background of canonical Watson-Crick base pairs. In this project, the structure of a 17mer mismatch GT DNA was carried out using NMR spectroscopy to identify the differences caused by the introduction of a non-canonical base pair on helical structure. The resulting structure was B-form in conformation and local helical distortions were observed about the GT mispair due primarily to its sheared orientation. The effect of mismatch orientation, sequence context and oligonucleotide length on mismatch stability was also investigated using UV absorbance melting and NMR spectroscopy. The results showed that substitution of a TG mispair for a GT mispair was accompanied by a small drop in melting temperature. It was also discovered that sequences in which purine-purine or pyrimidine-pyrimidine stacking occurred induced additional stability of the mismatch resulting in a higher melting temperature of the duplex.Affinity of mismatch GT DNA and its mismatch orientation, sequence context and length analogues for MutS was investigated by monitoring changes to the chemical shifts and linewidths of imino protons resonances during NMR titration. The results showed that MutS displayed higher affinity towards sequences which involved better stacking between the flanking base pairs and the GT/TG mispair.Analogous NMR structural investigations of 6-thioguanine modified 13mer GC DNA and its oxidised derivatives have been successfully carried out. The NMR structure was successfully determined of the former and the results obtained showed the effect on helical structure induced by the substitution of a different DNA lesion.Although the crystal structures of MutS bound to DNA mismatches have been known for a number of years, the analogous crystal structures of uncomplexed apo MutS have not been determined to date. Consequently, vital structural knowledge on the large change in conformation of MutS upon binding to the DNA mismatch is seriously lacking. We have successfully isolated the structurally and functionally important NTD of E. coli MutS and its labelled (13C, 15N) analogues and have shown that it is endowed with a stable, tertiary structural fold and well suited to NMR structure determination. This is exemplified by the assignments of several backbone amide and side chain resonances using isotope aided 3D NMR techniques.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The Athabasca University Digital Reading Room: Library resources for mobile students

This project has been designed to test the boundaries of Mlearning and to begin to build a platform for AU to raise an effective m-library. Building on the research conducted in Canada and abroad, the researchers are investigating PDAs and learning objects in order to maximize the potential of Mlearning. What constitutes an effective Mlibrary? Within the limits of this research investigation, an effective Mlibrary must store the contents in a format accessible and configurable by a wide variety of devices and software applications. Special programming is required to implement optimal delivery on a variety of devices and software applications. What resources can be made available in the Mlibrary (content and resource development)? It seems that a wide variety of resource types can be made available on mobile devices subject to formatting limitations. With appropriate programming there are few if any limitations on text displays and only size-comfort limitations on graphics, sound, and video. What are the technical difficulties in implementing the DRR on mobile devices? Because of the difference in the operating systems and the pocket browsers in the PPC and the POS, the CSS stylesheet cannot be implementd in a generic manner. This causes difficulties in designing accessibily/usabilty features for the two different systems

Restoring Hong Kong's landscar in the Anderson Quarry : an analysis of civic engagement strategies

published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

Radion Dynamics and Phenomenology in the Linear Dilaton Model

We investigate the properties of the radion in the 5D linear dilaton model arising from Little String Theory. A Goldberger-Wise type mechanism is used to stabilise a large interbrane distance, with the dilaton now playing the role of the stabilising field. We consider the coupled fluctuations of the metric and dilaton fields and identify the physical scalar modes of the system. The wavefunctions and masses of the radion and Kaluza-Klein modes are calculated, giving a radion mass of order the curvature scale. As a result of the direct coupling between the dilaton and Standard Model fields, the radion couples to the SM Lagrangian, in addition to the trace of the energy-momentum tensor. The effect of these additional interaction terms on the radion decay modes is investigated, with a notable increase in the branching fraction to photons. We also consider the effects of a non-minimal Higgs coupling to gravity, which introduces a mixing between the Higgs and radion modes. Finally, we calculate the production cross section of the radion at the LHC and use the current Higgs searches to place constraints on the parameter space.Comment: 28 pages, 7 figures; v2: error in radion-gauge boson Feynman rules corrected, version published in JHE

Hypothalamic AMP-Activated Protein Kinase Regulates Glucose Production

OBJECTIVE—The fuel sensor AMP-activated protein kinase (AMPK) in the hypothalamus regulates energy homeostasis by sensing nutritional and hormonal signals. However, the role of hypothalamic AMPK in glucose production regulation remains to be elucidated. We hypothesize that bidirectional changes in hypothalamic AMPK activity alter glucose production. RESEARCH DESIGN AND METHODS—To introduce bidirec-tional changes in hypothalamic AMPK activity in vivo, we first knocked down hypothalamic AMPK activity in male Sprague-Dawley rats by either injecting an adenovirus expressing the dominant-negative form of AMPK (Ad-DN AMPK2 [D157A]) or infusing AMPK inhibitor compound C directly into the medio-basal hypothalamus. Next, we independently activated hypotha-lamic AMPK by delivering either an adenovirus expressing the constitutive active form of AMPK (Ad-CA AMPK1312 [T172D]

Achiral dielectric metasurfaces for spectral and polarization control of valley specific light emission from monolayer MoS2

Excitons in two-dimensional transition metal dichalcogenides have a valley degree of freedom that can be optically accessed and manipulated for quantum information processing. Here, we integrate MoS2 with achiral silicon disk array metasurfaces to enhance and control valley-specific absorption and emission. Through the coupling to the metasurface Mie modes, the intensity and lifetime of the emission of neutral excitons, trions and defect bound excitons can be enhanced, while the spectral shape can be modified. Additionally, we demonstrate the symmetric enhancement of the degree-of-polarization (DOP) of neutral exciton and trions via valley-resolved PL measurements, and find that the DOP can be as high as 24% for exciton emission and 34% for trion emission at 100K. These results can be understood by analyzing the near-field impact of metasurface resonators on both the chiral absorption of MoS2 emitters as well as the enhanced emission from the Purcell effect. Combining Si-compatible photonic design with large-scale (mm-scale) 2D materials integration, our work makes an important step towards on-chip valleytronic applications approaching room-temperature operation