APPROACH Our approach is divided into four subtasks: Task 1: Forces and failure modes in suction cup attachments. Define assays to investigate cup failure modes. Task II: Assessing the impact of tags and surface attachments on cetaceans. Using Computational Fluid Dynamics we will assess the drag forces created by various suction cup and tag housing combinations. Task III: Engineered suction cup...

INTRODUCTION Basic daily activities, such as walking and climbing stairs produce forces on the acetabular cup that results in shear forces throughout the contacting surface producing acetabular cup micromotion. Minimizing micromotion of the acetabular component is critical to the long term survival of total hip arthroplasty. A typical cementless acetabular component is coated with a porous surf...

In this paper we show that the Breitenlohner-Maison prescription for treating the presence of chiral symmetry in Dimensional Regularization fits remarkably well with the framework of noncommutative geometry. In fact, it corresponds to taking the cup product of spectral triples, with a specific spectral triple Xz whose dimension spectrum is a single complex number z. We give a realization of Xz ...

We present here a combinatorial method for computing Steenrod squares of a simplicial set X . This method is essentially based on the determination of explicit formulae for the component morphisms of a higher diagonal approximation (i.e., a family of morphisms measuring the lack of commutativity of the cup product on the cochain level) in terms of face operators of X . A generalization of this ...

Let p ≥ 3 be a prime. We consider the cyclotomic extension Z (p) [ζ p 2 ] | Z (p) , with galois group G = (Z/p 2) *. Since this extension is wildly ramified, the Z (p) G-module Z (p) [ζ p 2 ] is not projective. We calculate its cohomology ring H * (G, Z (p) [ζ p 2 ]; Z (p)), carrying the cup product induced by the ring structure of Z (p) [ζ p 2 ]. Proceeding in a somewhat greater generality, ou...

We show a non-existence result for some class of equivariant maps between sphere bundles over tori. The notion of equivariant KO *-degree is used in the proof. As an application we have an inequality b + 2 (X) ≥ −sign (X)/8 + c(X) + ε(X) for a 4-dimensional connected closed oriented spin manifold X whose intersection form is indefinite, where c(X) is a non-negative integer determined by the cup...

The integer cohomology algebra of the complement of a complex subspace arrangement with geometric intersection lattice is completely determined by the combinatorial data of the arrangement. We give a combinatorial presentation of the cohomology algebra in the spirit of the Orlik-Solomon result on the cohomology algebras of complex hyperplane arrangements. Our methods are elementary: we work wit...

To Robert Rankin Let k be a number field, and let M be a pure motive of weight n over k. Assume that there is a non-degenerate pairing M × M → Q(−n). For example, M could arise from the cohomology in degree n of a projective, smooth, geometrically connected variety X of dimension n over k, and the pairing from the cup product. In this case, the pairing will be symplectic (alternating) if n is o...

INTRODUCTION The total hip replacement is a common surgical procedure in orthopaedics. However, the acetabular cup loosening is one of the major failure modes of cementless acetabular cup. Many researches point out that an unstable cup would induce a large micromotion under dynamic loading. This large micromotion would reduce the bone ongrowth on the cementless cup surface and prohibit the osse...

BACKGROUND Trabecular metal has shown promising results in experimental studies of bone ingrowth. Several clinical studies support these results. However, until now, no randomized clinical radiostereometric analysis (RSA) studies have been published. In this randomized RSA trial, we compared a new acetabular cup with a surface made of tantalum trabecular metal and a cup with a titanium fiber-me...