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But other operations can distinguish positive and negative zero ; for example , 1.0 / 0.0 has the value positive infinity , while the value of 1.0 / -0.0 is negative infinity . " While commissions study again and again the plight of the Black Belt and recommend the same or similar action plans of previously appointed commissions , while councils wring their hands over poverty and failure , while government and foundations mandate ineffective and costly programs without input from the very people they wish to aid , you act , " he said . The photographs themselves are the work of several photographers , while the catalogue of the photographs is the work of A. Zeno Shindler and William Henry Jackson .