American demand for this type of metallurgical coal has been relatively weak recently, says Macquarie analyst Curt Woodworth.

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In it, he uses eye drops made of a special riboflavin (a type of vitamin B) formulation and a very weak ultraviolet light to strengthen the collagen fibers in the eye.

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And that type of rapid slowdown can be a just as strong a warning sign as a weak job market or a demographic shift.

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