On the sustainability of web systems evolution

In the last twenty years, the evolution of web systems has been driven along three dimensions: the processes used to develop, evolve, maintain and re-engineer the systems themselves; the end products (the pages, content and links) of such processes; and finally the people dimension, with the extraordinary shift in how developers and users shape, interact and maintain the code and content that they put online. This paper reviews the questions that each of these dimensions has addressed in the past, and indicates which ones will need to be addressed in the future, in order for web system evolution to be sustainable. We show that the study on websites evolution has shifted from server- to client-side, focusing on better technologies and processes, and that the users becoming creators of content open several open questions, in particular the issue of credibility of the content created and the sustainability of such resources in the long term

Stress waves in transversely isotropic media: The homogeneous problem

The homogeneous problem of stress wave propagation in unbounded transversely isotropic media is analyzed. By adopting plane wave solutions, the conditions for the existence of the solution are established in terms of phase velocities and directions of particle displacements. Dispersion relations and group velocities are derived from the phase velocity expressions. The deviation angles (e.g., angles between the normals to the adopted plane waves and the actual directions of their propagation) are numerically determined for a specific fiber-glass epoxy composite. A graphical method is introduced for the construction of the wave surfaces using magnitudes of phase velocities and deviation angles. The results for the case of isotropic media are shown to be contained in the solutions for the transversely isotropic media

Wood formation, girth trunk increment and phenology of two tree species from Atlantic rain forest in southern Brazil growing in two different soil conditions.

WorldDendro 2010

Wave propagation in anisotropic medium due to an oscillatory point source with application to unidirectional composites

The far-field displacements in an infinite transversely isotropic elastic medium subjected to an oscillatory concentrated force are derived. The concepts of velocity surface, slowness surface and wave surface are used to describe the geometry of the wave propagation process. It is shown that the decay of the wave amplitudes depends not only on the distance from the source (as in isotropic media) but also depends on the direction of the point of interest from the source. As an example, the displacement field is computed for a laboratory fabricated unidirectional fiberglass epoxy composite. The solution for the displacements is expressed as an amplitude distribution and is presented in polar diagrams. This analysis has potential usefulness in the acoustic emission (AE) and ultrasonic nondestructive evaluation of composite materials. For example, the transient localized disturbances which are generally associated with AE sources can be modeled via this analysis. In which case, knowledge of the displacement field which arrives at a receiving transducer allows inferences regarding the strength and orientation of the source, and consequently perhaps the degree of damage within the composite

Monitoring tree growth and phenology in restored forests.

Resumo

Postanesthetic Severe Oral Angioedema in Patient's Taking Angiotensin-Converting Enzyme Inhibitor

Angiotensin-converting enzyme (ACE) inhibitors are the leading cause of a drug-induced angioedema. This occurrence is frequently underdiagnosed, but its relapse can be life-threatening. The authors' intention in reporting this clinical case is to sound a warning about reviewing attitudes and surveillance to try to improve patient perioperative safety