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On my computer , it took close to the same time with force as without . Appropriate response by public health agencies to requests for such investigations demands that the complexity of this area be recognized and , in addition , requires the possession and application of skills and knowledge that extend well beyond statistical and epidemiologic tools . Drug-resistant ( especially isoniazid-resistant ) tubercle bacilli may grow poorly or not at all on laboratory media ; they may lose or have diminished catalase activity ; and they may fail to produce progressive disease in guinea pigs , although not necessarily in humans . The first extreme is that all observed zeros are in effect sampling zeros : each worker has some nonzero probability of being off sick , and it is merely that some workers were not , in fact , off sick in our sample period . That dream was shattered by the illusion that the people of Paris and London and New York could simply go on with their lives while the people of Vilnius and Krakow and Prague were robbed of their independence , sent away in box cars , and machine-gunned in forests .