12,703 research outputs found
Current-driven skyrmion motion along disordered magnetic tracks
The motion of skyrmions along ferromagnetic strips driven by current pulses
is theoretically analyzed by means of micromagnetic simulations. Analytical
expressions describing the skyrmion dynamics during and after the current pulse
are obtained from an extended rigid skyrmion model, and its predictions are
compared with full micromagnetic simulations for perfect samples with a
remarkable agreement. The dynamics along realistic samples with random disorder
is also studied by both models. Our analysis describes the relevant ingredients
behind the current-driven skyrmion dynamics, and it is expected to be useful to
understand recent and future experimental.Comment: Micromagnetic simulations and analytical expressions describing the
dynamics of skyrmions under current-pulses along realistic strip
Civil organizations. More politics for less organisation: Aristotle´s social theory
There is a lack in analysing Third Sector from a philosophical perspective. It is very complicated to answer many questions that are arising: Why men are concerned to the problems other men are involved in? Which is the driving force of the Social Sector? Why are NGOs legitimated to support social matters? What have NGOs to do in the XIX century? This questions need to be answered to fix correctly future strategy, mission and objectives. It is necessary to build an ethical-political frame to understand how Third Sector works. This paper studies the relationship between NGO and beneficiary, the changes happened in the XX century and the challenges NGO need to face in the forthcoming years.Non Profit Organisations, Third Sector, Ethics, Ethical-political focus, Relationship, Liberty
The why, when, and how of Corporate Social Responsibility
Reflecting on the question of who is the principal subject of social responsibility in the business sphere, Greenfield sets out a number of common assumptions among practitioners in the field and tries to dismantle them through a critical review of recent literature. Some of his reflections need to be nuanced from an ethical basis and elaborated upon from a practical point of view. Taking as our starting point Greenfield´s conclusion "there is no such thing as business ethics, only ethics of individual business men and women", this article aims to look in more depth at the consequences of regulating personal ethics and referring it to an institution.Business ethics, Corporate social responsibility, Strategy
Exact Solutions of Integrable 2D Contour Dynamics
A class of exact solutions of the dispersionless Toda hierarchy constrained
by a string equation is obtained. These solutions represent deformations of
analytic curves with a finite number of nonzero harmonic moments. The
corresponding tau-functions are determined and the emergence of cusps is
studied.Comment: 13 pages, 3 figure
Genus-zero Whitham hierarchies in conformal-map dynamics
A scheme for solving quasiclassical string equations is developped to prove
that genus-zero Whitham hierarchies describe the deformations of planar domains
determined by rational conformal maps. This property is applied in normal
matrix models to show that deformations of simply-connected supports of
eigenvalues under changes of coupling constants are governed by genus-zero
Whitham hierarchies.Comment: 12 pages, 3 figure
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