In most cases, structural engineers assume a concrete floor to be a rigid diaphragm. Although this simplification is in most cases acceptable, it should be noted that such an assumption may be distrusted due to certain problems. Concrete structures with staggered shear walls are among those whose analysis should be conducted with special concern for the behavior of their floor diaphragms. Howev...

In buildings with triangular plan, the center of mass and rigidity cannot geometrically match all possible directions of the earthquake. This will result in torsional moments in the stories causing the building to rotate around the center of rigidity. In this paper, via response spectrum analysis (RSA) and nonlinear static analysis, the seismic behavior of 5-, 10- and 15-story steel structures ...

Using very weak criteria for what may constitute a noncommutative geometry, I show that a pseudo-Riemannian manifold can only be smoothly deformed into noncommutative geometries if certain geometric obstructions vanish. These obstructions can be expressed as a system of partial differential equations relating the metric and the Poisson structure that describes the noncommutativity. I illustrate...

Topological rigidity is an analogue of the Baum-Connes conjecture, and is motivated by Mostow rigidity and Margulis superrigidity. I will discuss some of the places where this heuristic reasoning fails, and the rigidity shows some cracks – that are rather different than the places where strong forms of the Baum-Connes conjecture fails.

1 The Proof Modulo some Analysis 1.1 Statement of the Result Given any metric space (X, d), a map H : X → X is BL (bi-lipshitz) if there is some constant K > 0 such that d(H(x), H(y)) ∈ [K, K] d(x, y), ∀x, y ∈ X. (1) Here is a limited form of Mostow Rigidity: Theorem 1.1 (Mostow) Suppose that M1 and M2 are both compact hyperbolic 3-manifolds. If there is a BL map f : M1 → M2 then there is an is...

Cell-extracellular matrix (ECM) interactions play a critical role in regulating cellular behaviors. Recent studies of cell-ECM interactions have mainly focused on the actomyosin based and adhesion mediated mechanosensing pathways to understand how individual mechanical signals in the cell microenvironment, such as matrix rigidity and adhesive ECM pattern, are sensed by the cell and further trig...

Criteria for the flexibility, rigidity, and almost rigidity of nonnormal affine toric varieties are obtained. For rigid varieties, automorphism groups explicitly calculated.

Static and dynamic deformabilities of erythrocytes are important determinants of microcirculatory blood flow. To determine the influence of increased cellular hemoglobin concentration on these properties, we quantitated static and dynamic deformabilities of isolated subpopulations of oxygenated normal and sickle erythrocytes with defined cell densities using micromechanical manipulations of ind...

This paper tests the ‘morale’ theory of downward nominal wage rigidity. This theory relies on workers disliking nominal pay cuts: cuts should make workers less happy. We investigate this using panel data on individual employees’ pay and satisfaction. We con...rm that nominal cuts do make workers less happy than if their pay had not fallen. But we ...nd no di¤erence in the e¤ect on happiness of ...