1,513 research outputs found
Preparing for a Postmethod Pedagogy: A Transformative Approach to Curriculum Development
The three parameters of postmethod pedagogy proposed by Kumaravadivelu (2001), particularly a pedagogy of possibility, are in line with and drew on the works of such critical pedagogists as Giroux (1988) whose idea of transformative intellectuals viewed it rightful for every individual teacher and learner to actively participate in the process of learning with their entire social, economic and political experiences; and even make reformations to the direction of pedagogy based on their understanding. However, curriculum development, as an integral part of pedagogy, may inhibit this transformative and dynamic learning by restricting teachers to set and prefabricated materials and guidelines. Nonetheless, teachers play a pivotal role in the realization of this transformative process since they are the executive recipients of curricula. This paper is an attempt to shed light on a transformative approach to curriculum development and holds, a transformative approach to curriculum development requires teachers to have a hand in curriculum development when they are invited by the curriculum to act so; and adapt or transform the curriculum when they are constrained by it
Social media in project management: A systematic narrative literature review
Despite the adoption of social media in many business operations, evidence suggests that the usage of social media for project management activities is scarce. Through this literature review, the paper seeks to clarify the scope of the available knowledge, highlight the significance of new research agendas and address the principal reason for the limited use of social media in project management. A literature review was conducted to analyze the benefits of using social media in project management along with the areas in which it is used, the threats, barriers and enablers of social media adoption. Key areas where social media is used in project management include requirements management, communication management, policymaking, knowledge management and collaboration. Social media usage has shown to improve information sharing, engagement and relationships. Threats include a negative impact on reputation, employee productivity and information privacy. The reviewed literature highlights that the lack of a social media adoption strategy is the principal reason for the limited use of social media in project management. This study contributes to both the project management practice and literature by introducing a model for social media adoption in project management
Non-contact rack and pinion powered by the lateral Casimir force
The lateral Casimir force is employed to propose a design for a potentially
wear-proof rack and pinion with no contact, which can be miniaturized to
nano-scale. The robustness of the design is studied by exploring the relation
between the pinion velocity and the rack velocity in the different domains of
the parameter space. The effects of friction and added external load are also
examined. It is shown that the device can hold up extremely high velocities,
unlike what the general perception of the Casimir force as a weak interaction
might suggest.Comment: 4 pages, submitted for publication on 17 Jan 0
Effect of alveolar ridge preservation with PDFDBA on orthodontic tooth movement rate, formation of gingival invagination and root resorption: A randomized, controlled pilot study
Tooth extraction results in resorptive remodeling of the alveolar bone, but alveolar ridge preservation procedure maintains the original shape of the extraction socket. This may be beneficial for space closure by orthodontic tooth movement (OTM). In the current pilot study for randomized controlled clinical trial the effect of alveolar ridge preservation with partial demineralized freezedried bone allograft (PDFDBA) on OTM rate, formation of gingival invagination and root resorption was evaluated. Both mandibular first premolars of 6 patients were extracted due to orthodontic treatment. In a split-mouth study design, alveolar ridge preservation was performed on one side, while the other side served as a control and the extraction socket healed naturally. After 6 weeks of healing period, the canines were moved to the extraction site to close the extraction space. Eight weeks later, the amount of OTM was measured. After space closure, the extraction sites were examined for the presence of gingival invagination. Root resorption was evaluated on digital panoramic radiographs. Photographs were taken for documentation. There was no significant difference in OTM rate between the ridge preserved areas and naturally healed sockets. Gingival invagination formed in 5 of 6 naturally healed sockets; none of the ridge preserved areas showed formation of gingival invagination. No root resorption was observed in any of the teeth adjacent to the extraction sites. Alveolar ridge preservation with PDFDBA has no effect on the rate of OTM and root resorption but prevents formation of gingival invagination during orthodontic space closure
Unveiling and Manipulating Hidden Symmetries in Graphene Nanoribbons
Armchair graphene nanoribbons are a highly promising class of semiconductors
for all-carbon nanocircuitry. Here, we present a new perspective on their
electronic structure from simple model Hamiltonians and
calculations. We focus on a specific set of nanoribbons of width ,
where is the number of carbon atoms across the nanoribbon axis and is a
positive integer. We demonstrate that the energy-gap opening in these
nanoribbons originates from the breaking of a previously unidentified hidden
symmetry by long-ranged hopping of -electrons and structural distortions
occurring at the edges. This hidden symmetry can be restored or manipulated
through the application of in-plane lattice strain, which enables continuous
energy-gap tuning, the emergence of Dirac points at the Fermi level, and
topological quantum phase transitions. Our work establishes an original
interpretation of the semiconducting character of armchair graphene nanoribbons
and offers guidelines for rationally designing their electronic structure
Dirac half-semimetallicity and antiferromagnetism in graphene nanoribbon/hexagonal boron nitride heterojunctions
Half-metals have been envisioned as active components in spintronic devices
by virtue of their completely spin-polarized electrical currents. Actual
materials hosting half-metallic phases, however, remain scarce. Here, we
predict that recently fabricated heterojunctions of zigzag nanoribbons embedded
in two-dimensional hexagonal boron nitride are half-semimetallic, featuring
fully spin-polarized Dirac points at the Fermi level. The half-semimetallicity
originates from the transfer of charges from hexagonal boron nitride to the
embedded graphene nanoribbon. These charges give rise to opposite energy shifts
of the states residing at the two edges while preserving their intrinsic
antiferromagnetic exchange coupling. Upon doping, an
antiferromagnetic-to-ferrimagnetic phase transition occurs in these
heterojunctions, with the sign of the excess charge controlling the spatial
localization of the net magnetic moments. Our findings demonstrate that such
heterojunctions realize tunable one-dimensional conducting channels of
spin-polarized Dirac fermions that are seamlessly integrated into a
two-dimensional insulator, thus holding promise for the development of
carbon-based spintronics
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