The equations of a planar elastica under pressure can be rewritten in useful form by parametrising the variables terms local orientation angle, $\theta$, instead arc length. This ``$\theta$-formulation'' lends itself to particularly easy boundary layer analysis limit weak bending stiffness. Within this parameterization, layers are located at inflexion points, where $\theta$ is extremum, and the...

We determine the equilibria of a rigid loop in the plane, subject to the constraints of fixed length and fixed enclosed area. Rigidity is characterized by an energy functional quadratic in the curvature of the loop. We find that the area constraint gives rise to equilibria with remarkable geometrical properties; not only can the Euler-Lagrange equation be integrated to provide a quadrature for ...

We study the buckling of a two-dimensional elastica floating on a bath of dense fluid, subjected to axial compression. The sinusoidal pattern predicted by the analysis of linear stability is shown to become localized above the buckling threshold. A nonlinear amplitude equation is derived for the envelope of the pattern. These results provide a simple interpretation to the wrinkle-to-fold transi...

Novel forests (NFs)-forests that contain a combination of introduced and native species-are a consequence of intense anthropogenic disturbances and the natural resilience of disturbed ecosystems. The extent to which NFs have similar forest function as comparable native secondary forests is a matter of debate in the scientific community. Little is known about the performance of individual specie...

Metal cofactors are necessary for the activity of alkylation by prenyl transfer in enzyme-catalyzed reactions. Rubber transferase (RuT, a cis-prenyl transferase) associated with purified rubber particles from Hevea brasiliensis, Parthenium argentatum and Ficus elastica can use magnesium and manganese interchangably to achieve maximum velocity. We define the concentration of activator required f...

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Moyamoya disease was originally defined as a characteristic syndrome of recurrent headaches, occlusion of the distal internal carotid arteries and the foggy (moyamoya) clusters of collateral vessels at the base of the brain as demonstrated by cerebral angiography. The etiology is unknown and pathobiology is poorly understood. We examined the intracranial arteries in 3 patients to demonstrate ch...