A new system to fuel loading-and control rod pattern optimization in boiling water reactors

A new system to optimize both control rod pattern and fuel-loading design in boiling water reactors is shown. The system is named OCOTH, and it is based on heuristic techniques such as genetic algorithms, neural networks, and ant colonies. Each heuristic technique is used to design a part of the optimization process. So, the neural network finds an initial fuel loading with a Haling burnup calculation. The ant colony system optimizes full-power control rod pattern of the initial fuel loading. Finally, the genetic algorithm optimizes fuel loading with the optimized control rod patterns. The ant colony system and the genetic algorithm perform an iterative loop until a stop criterion is fulfilled;for example, control rod pattern and fuel-loading convergence. The OCOTH system was tested in an equilibrium cycle of Mexico's Laguna Verde Nuclear Power Plant. We found very good results in control rod pattern and fuel-loading coupled optimization

Dermoscopy of acral melanoma: a multicenter study on behalf of the international dermoscopy society

Background: Most studies on dermoscopy of acral lesions were conducted in Asian populations. In this study, we analyzed these features in a predominantly Caucasian population. Objective: Estimate the prevalence of dermoscopic features in acral lesions, and assess their level of agreement between observers. Methods: In this retrospective multicenter study, 167 acral lesions (66 melanomas) were evaluated for 13 dermoscopic patterns by 26 physicians, via a secured Internet platform. Results: Parallel furrow pattern, bizarre pattern, and diffuse pigmentation with variable shades of brown had the highest prevalence. The agreement for lesion patterns between physicians was variable. Agreement was dependent on the level of diagnostic difficulty. Conclusion: Lesions with a diameter >1 cm were more likely to be melanoma. We found as well that a benign pattern can be seen in parts of melanomas. For this reason one should evaluate an acral lesion for the presence of malignant patterns first. © 2013 S. Karger AG, Basel