1,908 research outputs found

    North by Northwest : Information literacy at Yukon College and Lakehead University

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    In Northern communities, isolation is a fact of life and common southern "realities" like high-speed internet, libraries (both public and academic) within driving distance and f2f instruction are not the norm. Due to these factors, online instruction is a core component in northern academic institutions and as such requires a little bit more preparation. As well, another key factor to consider is the diverse student population: First Nations, mature, part-time, first generation university students, and professionals upgrading their credentials. The diverse academic backgrounds of these students makes designing the standard library tutorial a challenge; one size does not fit all in the north. At the same time, this might be the only way that students interact with a librarian so the online environment becomes significant to these students' academic studies (and hopefully success). So how does an academic library with such a variety of students a) reach these students? b) design online tutorials targeting a variety of learning styles? and c) assess whether any of this is working? This session will show you how to take a generic one hour information literacy class and turn it into an online session that will meet the needs of a diverse student population. The presenters will discuss effective pedagogical approaches to online instruction, how to teach specific e-resources and finally how to ensure that the students are actually finding the Library's e-resources and using them effectively and efficiently. This presentation won't focus as much on software, although we will be discussing what we use, it's more about how to use the software to teach InfoLit online effectively. We will conclude with a discussion on how to beta-test your new online approach to Information Literacy Instruction before launching it live for the students. So, come to this session and see how two northern (Ontario and Yukon) librarians are devising new and alternative methods of reaching out to students via a variety of methods and assessing their efforts. How, in fact, we have to examine "every angle" such as mode of delivery, type of student, pedagogical theory, etc. to ensure that we are serving our diverse populations well and contributing to the retention and success of these students

    Low-frequency oscillations of the Atlantic Ocean meridional overturning circulation in a coupled climate model

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    International audienceUsing a 3-dimensional climate model of intermediate complexity we show that the overturning circulation of the Atlantic Ocean can vary at multicentennial-to-millennial timescales for present-day boundary conditions. A weak and continuous freshwater input into the Labrador Sea pushes the overturning circulation of the Atlantic Ocean into a bi-stable regime, characterized by phases of active and inactive deep-water formation in the Labrador Sea. In contrast, deep-water formation in the Nordic Seas is active during all phases of the oscillations. The actual timing of the transitions between the two circulation states occurs randomly. The oscillations constitute a 3-dimensional phenomenon and have to be distinguished from low-frequency oscillations seen previously in 2-dimensional models of the ocean. A conceptual model provides further insight into the essential dynamics underlying the oscillations of the large-scale ocean circulation. The model experiments indicate that the coupled climate system can exhibit unforced climate variability at multicentennial-to-millennial timescales that may be of relevance for Holocene and future climate variations

    Low-frequency oscillations of the Atlantic Ocean meridional overturning circulation in a coupled climate model

    No full text
    International audienceUsing a 3-dimensional climate model of intermediate complexity we show that the overturning circulation of the Atlantic Ocean can vary at multicentennial-to-millennial timescales for modern boundary conditions. A continuous freshwater perturbation in the Labrador Sea pushes the overturning circulation of the Atlantic Ocean into a bi-stable regime, characterized by phases of active and inactive deep-water formation in the Labrador Sea. In contrast, deep-water formation in the Nordic Seas is active during all phases of the oscillations. The actual timing of the transitions between the two circulation states occurs randomly. The oscillations constitute a 3-dimensional phenomenon and have to be distinguished from low-frequency oscillations seen previously in 2-dimensional models of the ocean. A conceptual model provides further insight into the essential dynamics underlying the oscillations of the large-scale ocean circulation. The model experiments indicate that the coupled climate system can exhibit unforced climate variability at multicentennial-to-millennial timescales that may be of relevance for Holocene climate variations

    Mechanics of planar periodic microstructures

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    Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaf 31).The deformation of two-dimensional periodically patterned elastomeric sheets has been shown to trigger interesting pattern changes that are both repeatable and predictable (Bertoldi et al., 2007). Here, both square and hexagonal lattices of these sheets under axial compression are investigated both with empty voids, and also with inclusions introduced into the voids in specified patterns. A local buckling instability in the square lattice and shear instability in the hexagonal lattice trigger the change in pattern in the structure upon reaching a critical stress during compression. Experimental and numerical results are obtained that show the ability to predict and control the pattern changes that are triggered. The shape of the pattern change, the areas of the lattice in which it is triggered, and the extent to which the pattern is accentuated can all be controlled in a predictable manner. While the results here are on the millimeter length scale, they should also be applicable at the micro- and nano-scales, leading to photonic and phononic applications.by Sharon M. Prange.S.B

    Are elevated moist layers a blind spot for hyperspectral infrared sounders? A model study

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    The ability of the hyperspectral satellite-based passive infrared (IR) instrument IASI to resolve elevated moist layers (EMLs) within the free troposphere is investigated. EMLs are strong moisture anomalies with significant impact on the radiative heating rate profile and typically coupled to freezing level detrainment from convective cells in the tropics. A previous case study by indicated inherent deficiencies of passive satellite-based remote sensing instruments in resolving an EML. In this work, we first put the findings of into the context of other retrieval case studies of EML-like structures, showing that such structures can in principle be retrieved, but retrievability depends on the retrieval method and the exact retrieval setup. To approach a first more systematic analysis of EML retrievability, we introduce our own basic optimal estimation (OEM) retrieval, which for the purpose of this study is based on forward-modelled (synthetic) clear-sky observations. By applying the OEM retrieval to the same EML case as , we find that a lack of independent temperature information can significantly deteriorate the humidity retrieval due to a strong temperature inversion at the EML top. However, we show that by employing a wider spectral range of the hyperspectral IR observation, this issue can be avoided and EMLs can generally be resolved. We introduce a new framework for the identification and characterization of moisture anomalies, a subset of which are EMLs, to specifically quantify the retrieval's ability to capture moisture anomalies. The new framework is applied to 1288 synthetic retrievals of tropical ocean short-range forecast model atmospheres, allowing for a direct statistical comparison of moisture anomalies between the retrieval and the reference dataset. With our basic OEM retrieval, we find that retrieved moisture anomalies are on average 17 % weaker and 15 % thicker than their true counterparts. We attribute this to the retrieval smoothing error and the fact that rather weak and narrow moisture anomalies are most frequently missed by the retrieval. Smoothing is found to also constrain the magnitude of local heating rate extremes associated with moisture anomalies, particularly for the strongest anomalies that are found in the lower to mid troposphere. In total, about 80 % of moisture anomalies in the reference dataset are found by the retrieval. Below 5 km altitude, this fraction is only of the order of 52 %. We conclude that the retrieval of lower- to mid-tropospheric moisture anomalies, in particular of EMLs, is possible when the anomaly is sufficiently strong and its thickness is at least of the order of about 1.5 km. This study sets the methodological basis for more comprehensively investigating EMLs based on real hyperspectral IR observations and their operational products in the future

    A new Proposal for a Quasielectron Trial Wavefunction for the FQHE on a Disk

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    In this letter, we propose a new quasielectron trial wavefunction for NN interacting electrons in two dimensions moving in a strong magnetic field in a disk geometry. Requiring that the trial wavefunction exhibits the correct filling factor of a quasielectron wavefunction, we obtain N+1N+1 angular momentum eigenfunctions. The expectation values of the energy are calculated and compared with the data of an exact numerical diagonalization.Comment: 8 page

    Non-linear Resistivity of a Two-Dimensional Electron Gas in a Magnetic Field

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    We develop a theory of nonlinear response to an electric field of a two-dimensional electron gas (2DEG) placed in a classically strong magnetic field. The latter leads to a non-linear current-voltage characteristic at a relatively weak electric field. The origin of the non-linearity is two-fold: the formation of a non-equilibrium electron distribution function, and the geometrical resonance in the inter-Landau-levels transitions rates. We find the dependence of the current-voltage characteristics on the electron relaxation rates in the 2DEG.Comment: 4 pages, 2 figure

    North by Northwest : Information literacy at Yukon College and Lakehead University

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    In Northern communities, isolation is a fact of life and common southern "realities" like high-speed internet, libraries (both public and academic) within driving distance and f2f instruction are not the norm. Due to these factors, online instruction is a core component in northern academic institutions and as such requires a little bit more preparation. As well, another key factor to consider is the diverse student population: First Nations, mature, part-time, first generation university students, and professionals upgrading their credentials. The diverse academic backgrounds of these students makes designing the standard library tutorial a challenge; one size does not fit all in the north. At the same time, this might be the only way that students interact with a librarian so the online environment becomes significant to these students' academic studies (and hopefully success). So how does an academic library with such a variety of students a) reach these students? b) design online tutorials targeting a variety of learning styles? and c) assess whether any of this is working? This session will show you how to take a generic one hour information literacy class and turn it into an online session that will meet the needs of a diverse student population. The presenters will discuss effective pedagogical approaches to online instruction, how to teach specific e-resources and finally how to ensure that the students are actually finding the Library's e-resources and using them effectively and efficiently. This presentation won't focus as much on software, although we will be discussing what we use, it's more about how to use the software to teach InfoLit online effectively. We will conclude with a discussion on how to beta-test your new online approach to Information Literacy Instruction before launching it live for the students. So, come to this session and see how two northern (Ontario and Yukon) librarians are devising new and alternative methods of reaching out to students via a variety of methods and assessing their efforts. How, in fact, we have to examine "every angle" such as mode of delivery, type of student, pedagogical theory, etc. to ensure that we are serving our diverse populations well and contributing to the retention and success of these students
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