A connected Riemannian manifold (M,g) is said to be isotropy irreducible if for each point p ∈ M the isotropy group Hp, i.e. all isometries of g fixing p, acts irreducibly on TpM via its isotropy representation. This class of manifolds is of great interest since they have a number of geometric properties which follow immediately from the definition. By Schur’s lemma the metric g is unique up to...

BACKGROUND Pulmonary venous Doppler (PVD) flow patterns in the fetus with hypoplastic left heart syndrome (HLHS) have been correlated with restrictive interatrial communication or intact atrial septum (RAS) postnatally; however, the ability of PVD to identify the neonate requiring emergent atrial septoplasty (EAS) for severe left atrial hypertension and hypoxemia has not been critically evaluat...

The movement of a persons eyes is an interesting factor to study in different research areas where attention is important, for example driving. In 2004 the Swedish national road and transport research institute (VTI) introduced Simulator III – their third generation of driving simulators. Inside Simulator III a camera based eye tracking system is installed that records the eye movements of the ...

OBJECTIVE A less invasive method to assess internal thoracic artery (ITA) graft function after coronary artery bypass grafting (CABG) is desired. This study reports the novel method to estimate ITA graft function using CT angiography. MATERIALS AND METHODS Fifty ITA grafts were assessed. Hounsfield Unit transition of each graft on the same cross section was detected during the Test Bolus Inje...

Given a transversely projective foliation F on a C∞ manifold M and a nonnegative integer k, a transversal differential operator DF (2k + 1) of order 2k + 1 from N⊗k to N⊗(−k−1) is constructed, where N denotes the normal bundle for the foliation. There is a natural homomorphism from the space of all infinitesimal deformations of the transversely projective foliation F to the first cohomology of ...

Tissue microstructure, in particular the alignment of myocytes (fibre direction) and their lateral organisation into sheets, is fundamental to cardiac function. We studied the effect of microstructure on contraction in a computational model of rat left ventricular electromechanics. Different fibre models, globally rule-based or locally optimised to DT-MRI data, were compared, in order to unders...

Fiber-reinforced rubberlike materials commonly used in tires undergo large deformations and exhibit different responses in tension and compression along the fiber direction. Assuming that the response of a fiber-reinforced rubberlike material can be modeled as transversely isotropic with the fiber direction as the axis of transverse isotropy, we express the stored energy function in terms of th...

We determined that the electromagnetic vertical transverse isotropic response in a layered earth can be obtained by solving two equivalent scalar equations, which were for the vertical electric field and for the vertical magnetic field, involving only a scalar global reflection coefficient. Besides the complete derivation of the full electromagnetic response, we also developed the corresponding...

This study addresses the stochastic modeling of media whose elasticity tensor exhibits uncertainties on the material symmetry class to which it belongs. More specifically, we focus on the construction of a probabilistic model which allows realizations of random elasticity tensors to be simulated, under the constraint that the mean distance (in a sense to be defined) to a given class of material...