Abstract
We discuss the writing of arc-induced long-period fiber gratings to be used as optical filters in Er/Yb fiber lasers and for flattening the gain spectra of Er-doped fiber amplifiers. A new approach for the fabrication of filters with complex profiles is also presented. (c) 2008 Wiley Periodicals, Inc.

Abstract
ToonTalk is a child-oriented programming language whose environment is an animated virtual world, with objects that children can pick up and use as in a game, such as birds, trucks, and robots, providing direct child-oriented metaphors for programming constructs. Actions performed by a programmer's avatar with these objects are both code and coding. ToonTalk is a powerful system, not just a "toy" system: it is based upon concurrent constraint programming languages, and programs written in languages such as Flat Guarded Horn Clauses and Flat Concurrent Prolog can be straightforwardly constructed in ToonTalk. However, there is not a specification of ToonTalk, for ready implementation in other environments. We propose that the ToonTalk language lies not in the animations displayed by the current environment, but on the actions performed by the programmer with virtual world objects; we present a description and analysis of the methods the ToonTalk language provides to programmers for expressing programs.

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Abstract
The electric arc technique is used to apodize fiber Bragg gratings (FBGs). Arc discharges applied to the ends of the grating produce a smoothing of the refractive-index modulation profile reducing the sidelobes of the reflection spectrum at longer wavelengths. A sidelobe reduction of 17 dB was obtained. (c) 2007 Wiley Periodicals, Inc.

Abstract
Nesting problems are particularly hard combinatorial problems. They involve the positioning of a set of small arbitrarily-shaped pieces on a large stretch of material, without overlapping them. The problem constraints are bidimensional in nature and have to be imposed on each pair of pieces. This all-to-all pattern results in a quadratic number of constraints. Constraint programming has been proven applicable to this category of problems, particularly in what concerns exploring them to optimality. But it is not easy to get effective propagation of the bidimensional constraints represented via finite-domain variables. It is also not easy to achieve incrementality in the search for an improved solution: an available bound on the solution is not effective until very late in the positioning process. In the sequel of work on positioning non-convex polygonal pieces using a CLP model, this work is aimed at improving the expressiveness of constraints for this kind of problems and the effectiveness of their resolution using global constraints. A global constraint "outside" for the non-overlapping constraints at the core of nesting problems has been developed using the constraint programming interface provided by Sicstus Prolog. The global constraint has been applied together with a specialized backtracking mechanism to the resolution of instances of the problem where optimization by Integer Programming techniques is not considered viable. The use of a global constraint for nesting problems is also regarded as a first step in the direction of integrating Integer Programming techniques within a Constraint Programming model.

Abstract