During breast radiotherapy treatment, the contralateral breast receives radiation doses to the skin and subcutaneous tissue caused mainly from incident electron contamination and low energy photon scatter radiation. Measurements have shown that for a typical hybrid tangential treatment, these dose levels can be up to 17% of maximum applied prescription dose if no shielding is used during the tr...

Clinical problems with noncemented total hip arthroplasty (THA) stems, directly or indirectly related to load transfer, include mid-thigh pain due to relative (micro) motions or excessive endosteal interface stresses, subsidence and loosening due to inadequate primary stability and fit, and proximal femoral bone atrophy due to stress shielding. In this article, the load-transfer mechanisms asso...

The advent of 'biological internal fixation' is an important development in the surgical management of fractures. Locked nailing has demonstrated that flexible fixation without precise reduction results in reliable healing. While external fixators are mainly used today to provide temporary fixation in fractures after severe injury, the internal fixator offers flexible fixation, maintaining the ...

Crack tip shielding phenomena, whereby the "effective crack-driving force" actually experienced at the crack tip is locally reduced, are examined with reference to fatigue crack propagation behavior in metals, composites and ceramics. Sources of shielding are briefly described in terms of mechanisms relying on the production of elastically constrained zones which envelop the crack (zone shieldi...

Effective radiation shielding is imperative to safe operation of modern Medical Cyclotrons producing large activities of short-lived radioisotopes on a commercial basis. Like the containment shielding of Medical Linear Accelerators (1), the optimal shielding design of Medical Cyclotrons demands a careful balance between the radiological, economical and often the sociopolitical factors. One is r...

Radar reflectivity (Zh), differential reflectivity (Zdr), and specific differential phase (Kdp) measured from the operational, polarimetric weather radar located in Trappes, France, were used to examine the effects of radar beam shielding on rainfall estimation. The objective of this study is to investigate the degree of immunity of Kdp-based rainfall estimates to beam shielding for C-band rada...

Action of electric and magnetic fields and their interaction effects are the basis of operation of every electrical and electronic instrument. But such action fields could also cause serious problems to the functioning of those instruments if they act on them unnecessarily, to the extreme, failure of the system may also occur. To avoid such unpleasant consequences arising out of unwanted electr...

While shielding in collisional, strongly magnetized (one-dimensional) plasmas obeys the standard Debye result, shielding in collisionless, immobile ion plasmas is far more complex than commonly believed. In some circumstances, the plasma will antishield a positive test charge; i.e., the plasma becomes more positive in the neighborhood of a positive test charge. When shielding does occur, it res...

We investigate the relationship between the internal structure of the firm and the extent of flexibility of its technology. We demonstrate that increased vertical separation within the firm as implied, for instance, by subcontracting or by additional vertical layers of management yields investment in a more flexible technology. In contrast, increased horizontal separation as implied by lack of ...