Let G = HoQ be a split extension of nite groups. A theorem of Charlap and Vasquez gives an explicit description of the di erentials d2 in the Lyndon-Hochschild-Serre spectral sequence of the extension with coe cients in a eld k. We generalize this to give an explicit description of all the dr (r 2) in this case. The generalization is obtained by associating to the group extension a new twisting...

The goal of this paper is to express the Bach tensor of a four– dimensional conformal geometry of an arbitrary signature by the Cartan normal conformal (CNC) connection. We show that the Bach tensor can be identified with the Yang–Mills current of the connection. It follows from that result that a conformal geometry whose CNC connection is reducible in an appropriate way has a degenerate Bach t...

This paper gives a short summary of the central role played by Ed Brown’s “twisting cochains” in higher FranzReidemeister (FR) torsion and higher analytic torsion. Briefly, any fiber bundle gives a twisting cochain which is unique up to fiberwise homotopy equivalence. However, when they are based, the difference between two of them is a higher algebraic K-theory class measured by higher FR tors...

The goal of this paper is to express the Bach tensor of a four dimensional conformal geometry of an arbitrary signature by the Cartan normal conformal (CNC) connection. We show that the Bach tensor can be identified with the Yang–Mills current of the connection. It follows from that result that a conformal geometry whose CNC connection is reducible in an appropriate way has a degenerate Bach te...

The paper discusses the possibility to control coupled bending-twisting vibrations of composite wing by means monoclinic structures in reinforcement plating. Decomposing potential straining energy and kinetic natural vibration modes into interacting non-interacting parts, it became possible introduce two coefficients that integrally consider effect geometry structure upon dynamic response param...

Axial twisting of the torso has been identified via epidemiologic studies as a significant risk factor for occupationally-related low back disorders. However, only recently have biomechanical studies been able to describe how twisting is accomplished through the use of the trunk musculature. These studies have been performed on subjects whose torso twists were performed in an upright posture. I...

Occupational-related low back disorders are the leading cause of lost work days as well as the most costly occupational safety and health problem facing industry today. Twisting has been found to be associated with lower back pain (Frymoyer, 1983). Previous biomechanical measures of twisting allowed ancillary moments and forces in addition to the twisting exertion. This confounding makes it dif...

1. The campaniform sensilla on the wings of the locust are strain-sensitive mechanoreceptors that provide proprioceptive feedback about wing forces, particularly aerodynamic lift, experienced during flight. They can be excited by imposed deformations of the wing, including those caused by imposed wing twisting. The afferents of the single subcostal group of sensilla on the hindwing had the same...

This article proposes a finite-time disturbance observer-based modified super-twisting algorithm (FDO-STA) for disturbed high-order integrator-chain systems under matched and mismatched disturbances. We first design observer estimation, in which we show the convergence of estimation errors to zero. Second, by employing estimates disturbances their derivatives, new dynamic sliding surface is der...