A Theory of Wage Dispersion and Job Market Segmentation.

Job market segmentation refers to the idea that there tends to be a correlation among high wages, high productivity, high capital intensity, high value added, few quits relative to layoffs, and low labor turnover. This paper develops a model of wage dispersion and job market segmentation based on the very sparce assumption that the only departure from a strictly orthodox neoclassical world consists of wages being sticky in the short run. Implications of the model are explored and discussed. Copyright 1989, the President and Fellows of Harvard College and the Massachusetts Institute of Technology.

Effects of round bale feeding sites on soil fecal bacteria and nutrient concentrations

An experiment was conducted over seven months (January to July 2003) to evaluate fecal bacteria and nutrient concentrations in soil surrounding round bale feeders at winter feeding sites. Six-inch soil samples were taken each month from a total of ten feeding sites, at distances of 10, 40, 70, and 100 feet from each feeder. Soil samples were taken before (January) livestock access to the sites, during (February, March, and April) the feeding period, and after (May, June, and July) cattle had been removed from the sites. Results indicate that fecal bacteria concentrations increased over the duration of feeding period and were greatest at close proximity to round bale feeders. The data suggest that environmental contamination due to fecal bacteria in the soil can occur up to 100 feet from the feeding site. For soil nutrients, the greatest increase generally occurred at 10 feet from the feeders, with few differences thereafter

Effect of resin disinfectants-I3 and -I5 on Giardia muris and Giardia lamblia.

The resin-I5 column developed in our laboratories rendered aqueous suspensions containing up to 5 X 10(4) cysts of Giardia muris or Giardia lamblia per ml incapable of excystation. The inhibition of excystation was effective at both 4 and 25 degrees C. The addition of Na2S2O3 to column eluates containing cysts appeared to partially reverse the disinfectant action, and the reversal was more pronounced at 4 degrees C than at 25 degrees C. In contrast, the rapid removal of cysts from the column eluates by centrifugation and filtration or the use of other reductants, notably cysteine and glutathione, did not similarly reverse the disinfectant properties of the column. Based on these data, we suggest that the disinfecting agent is acquired by the cyst in its passage through the resin column and that either the disinfecting agent or its reaction can be partially and specifically neutralized by Na2S2O3. We hypothesize that the time between disinfectant acquisition and activity is a function of the thickness of the Giardia cyst wall and consequently takes longer at the lower temperature. Nevertheless, resin-I5 appears to inactivate a larger number of cysts in a shorter period of time with lower residual halogen levels than do agents of other published methods