Objectives. To examine the association between maternal leisure time physical activity and mode of delivery. Study Design. Population-based multicentre cohort. From the Danish Dystocia Study, we included 2,435 nulliparous women, who delivered a singleton infant in cephalic presentation at term after spontaneous onset of labor in 2004-2005. We analysed mode of delivery according to self-reported...

Physical system modeling benefits from the use of implicit equations because it is often an intuitive way to describe physical constraints and behaviors. To achieve efficient models, model abstraction may lead to idealized component behavior that switches between modes of operation (e.g., an electrical diode may be on or off) based on inequalities (e.g., voltage > 0). In an explicit representat...

This paper investigates a multi-mode MAC protocol suite for use in a heterogeneous underwater network. Modems from different manufacturers may employ different physical layers and MAC protocols. If multiple modems operating in the same or overlapping frequency bands are deployed in the same geographic area, they cannot function correctly due to interference. We propose a mechanism to achieve co...

Bushes of normal modes represent exact mathematical objects describing specific dynamical regimes in nonlinear mechanical systems with point or space symmetry. In the present paper, we outline the bush theory and illustrate it with some bushes of small dimensions in octahedral mechanical structures.

A treatment in a neighborhood and at a point of the equivalence principle on the basis of derivations of the tensor algebra over a manifold is given. Necessary and sufficient conditions are given for the existence of local bases, called normal frames, in which the components of derivations vanish in a neighborhood or at a point. These frames (bases), if any, are explicitly described and the pro...