69,846 research outputs found
FearNot! An Anti-Bullying Intervention: Evaluation of an Interactive Virtual Learning Environment
Original paper can be found at: http://www.aisb.org.uk/publications/proceedings.shtm
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The Human Brain: A Multimedia Tutorial For The Independent Learner
The Human Brain is a multimedia, interactive, computer-based tutorial on the structure and function of the human nervous system. In creating it, we aim to solve a number of problems, both subject specific and general. As a subject, the structure and function of the nervous system is difficult to teach using traditional methods and there is a lack of integration in the teaching of structure and function. More generally, we are concerned with the difficulties of both assessing student understanding of a particular subject and remedying any deficiencies when the student is learning independently. Finally, we hope to resolve the conflict between linear and explorative modes of presentation of material in a teaching system
On the Theory of Killing Orbits in Space-Time
This paper gives a theoretical discussion of the orbits and isotropies which
arise in a space-time which admits a Lie algebra of Killing vector fields. The
submanifold structure of the orbits is explored together with their induced
Killing vector structure. A general decomposition of a space-time in terms of
the nature and dimension of its orbits is given and the concept of stability
and instability for orbits introduced. A general relation is shown linking the
dimensions of the Killing algebra, the orbits and the isotropies. The
well-behaved nature of "stable" orbits and the possible miss-behaviour of the
"unstable" ones is pointed out and, in particular, the fact that independent
Killing vector fields in space-time may not induce independent such vector
fields on unstable orbits. Several examples are presented to exhibit these
features. Finally, an appendix is given which revisits and attempts to clarify
the well-known theorem of Fubini on the dimension of Killing orbits.Comment: Latex, 19 pages, no figur
A two-compartment mechanochemical model of the roles of\ud transforming growth factor β and tissue tension in dermal wound healing
The repair of dermal tissue is a complex process of interconnected phenomena, where cellular, chemical and mechanical aspects all play a role, both in an autocrine and in a paracrine fashion. Recent experimental results have shown that transforming growth factor−β (TGFβ) and tissue mechanics play roles in regulating cell proliferation, differentiation and the production of extracellular materials. We have developed a 1D mathematical model that considers the interaction between the cellular, chemical and mechanical phenomena, allowing the combination of TGFβ and tissue stress to inform the activation of fibroblasts to myofibroblasts. Additionally, our model incorporates the observed feature of residual stress by considering the changing zero-stress state in the formulation for effective strain. Using this model, we predict that the continued presence of TGFβ in dermal wounds will produce contractures due to the persistence of myofibroblasts; in contrast, early elimination of TGFβ significantly reduces the myofibroblast numbers resulting in an increase in wound size. Similar results were obtained by varying the rate at which fibroblasts differentiate to myofibroblasts and by changing the myofibroblast apoptotic rate. Taken together, the implication is that elevated levels of myofibroblasts is the key factor behind wounds healing with excessive contraction, suggesting that clinical strategies which aim to reduce the myofibroblast density may reduce the appearance of contractures
A fibrocontractive mechanochemical model of dermal wound\ud closure incorporating realistic growth factor kinetics
Fibroblasts and their activated phenotype, myofibroblasts, are the primary cell types involved in the contraction associated with dermal wound healing. Recent experimental evidence indicates that the transformation from fibroblasts to myofibroblasts involves two distinct processes: the cells are stimulated to change phenotype by the combined actions of transforming growth factor β (TGFβ) and mechanical tension. This observation indicates a need for a detailed exploration of the effect of the strong interactions between the mechanical changes and growth factors in dermal wound healing. We review the experimental findings in detail and develop a model of dermal wound healing that incorporates these phenomena. Our model includes the interactions between TGFβ and collagenase, providing a more biologically realistic form for the growth factor kinetics than those included in previous mechanochemical descriptions. A comparison is made between the model predictions and experimental data on human dermal wound healing and all the essential features are well matched
Decay of an isolated monopole into a Dirac monopole configuration
We study numerically the detailed structure and decay dynamics of isolated
monopoles in conditions similar to those of their recent experimental
discovery. We find that the core of a monopole in the polar phase of a spin-1
Bose-Einstein condensate contains a small half-quantum vortex ring. Well after
the creation of the monopole, we observe a dynamical quantum phase transition
that destroys the polar phase. Strikingly, the resulting ferromagnetic order
parameter exhibits a Dirac monopole in its synthetic magnetic field.Comment: 6 pages, 5 figure
The School Improvement Partnership Programme: Using Collaboration and Enquiry to tackle Educational Inequity
No abstract available
Effect of magnetic field on the phase transition in a dusty plasma
The formation of self-consistent crystalline structure is a well-known
phenomenon in complex plasmas. In most experiments the pressure and rf power
are the main controlling parameters in determining the phase of the system. We
have studied the effect of externally applied magnetic field on the
configuration of plasma crystals, suspended in the sheath of a radio-frequency
discharge using the Magnetized Dusty Plasma Experiment (MDPX) device.
Experiments are performed at a fixed pressure and rf power where a crystalline
structure is formed within a confining ring. The magnetic field is then
increased from 0 to 1.28 T. We report on the breakdown of the crystalline
structure with increasing magnetic field. The magnetic field affects the
dynamics of the plasma particles and first leads to a rotation of the crystal.
At higher magnetic field, there is a radial variation (shear) in the angular
velocity of the moving particles which we believe leads to the melting of the
crystal. This melting is confirmed by evaluating the variation of the pair
correlation function as a function of magnetic field.Comment: 9 pages, 5 figure
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