In this paper symbolic quantifier elimination methods are used to explore the fragility of feedback compensators, and to design feedback systems with non-fragile compensators. A compensator is said to be fragile if given variations in compensator parameters result in significant deterioration of feedback performance. The issue of fragility is important in understanding the level of acurracy req...

We analyze and explore option fragility, the notion that option incentives are fragile due to their non-linear payoff structure. Option incentives become weaker as options fall underwater, leading to pressures to reprice options or restore incentives through additional grants of equitybased pay. We build a detailed data set on executives’ portfolios of stock and options and find that executive ...

Although the pulmonary capillaries were discovered in 1661, the ultrastructure of the wall was not elucidated until 60 years ago. Electron micrographs then showed that only 0.2 μm of tissue separated the capillary endothelium from the alveolar space over much of the area. In retrospect this vanishingly small protective layer should have alerted physiologists to the potential fragility of the ca...

BACKGROUND Osteoporosis and associated fragility fractures are a major health problem; they are more common in women over 50 years old. Fracture liaison nurses have been widely used in secondary care to promote the recognition of fragility fractures and to promote the use of bone-sparing medication to reduce the risk of recurrent facture. OBJECTIVE Audit the impact of a primary care based fra...

In the scope of a scenario-based risk analysis, this study aims to quantify and rank various types of epistemic uncertainties that enter into the derivation of fragility functions for common buildings. Using a numerical model of a test structure (a reinforced concrete five-story building with infill panels on the first two floors), a first type of uncertainty is introduced, consisting of the me...

Chromosome fragility in two families not exhibiting amplification of the CGG trinucleotide associated with the fragile X site has been examined. Fluorescence in situ hybridisation with cosmid DNA from loci immediately flanking FRAXA and other distal loci have confirmed that cytogenetic fragility in these subjects is the result of expression of a new folate sensitive fragile X site, FRAXE.

We simulate binary soft-disk systems in two dimensions and investigate how the dynamics slow as the area fraction is increased toward the glass transition. The "fragility" quantifies how sensitively the relaxation time scale depends on the area fraction, and the fragility strongly depends on the composition of the mixture. We confirm prior results for mixtures of particles with similar sizes, w...

In the present study, the authors investigated chromosomal fragility in patients with schizophrenia, and compared the patients, who were positive for minor physical anomalies (MPAs) with those who were negative for MPAs in respect to chromosome fragility. 44 patients with schizophrenia were examined and compared to 23 matched healthy controls. A modified Waldrop-scale was used for evaluation of...

Retrofitted bridge fragility curves provide a powerful tool for assessing the effect of retrofit measures on the seismic performance of different bridge types under a range of loading levels. Traditional methods for retrofit assessment typically evaluate the effectiveness of retrofit based on the performance of individual components. However, the use of fragility curves for retrofitted bridges ...

Skin fragility refers to a large group of conditions in which the ability of the skin to provide protection against trivial mechanical trauma is diminished, resulting in the formation of blisters, erosions, wounds, or scars. Acquired and physiological skin fragility is common; genetic disorders are rare but give insight into the molecular mechanisms ensuring skin stability. The paradigm is repr...