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The influence of soil macro-porosity and manure on atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine) transport was investigated under laboratory conditions using disturbed and undisturbed soil columns. The macro-porosity in the soil column was obtained with CT scanning technique. Liquid manure was applied at the surface of soil column, 19 cm long and 8 cm in diameter, at a rate of 60 m3/ha. Experimental results revealed that atrazine moves faster through the soils in the presence of manure compared to soil without application of manure. The average time for elusion and the relative peak concentration in the disturbed soil column without manure was 14.5 h and 3.1%, respectively compared to 11.0 h and 6.9% in the presence of manure, respectively. Similar behavior was observed in the case of disturbed soil columns. Soil macro-porosity has shown large impact on atrazine transport, especially in the presence of manure.

The objective is to provide insight to understanding public health officials' needs and promote access to data repositories and communication tools.Survey questions were identified by a focus group with members drawn from the fields of librarianship, public health, and informatics. The resulting comprehensive information needs survey, organized in five distinct broad categories, was distributed to 775 Tennessee public health workers from ninety-five counties in 1999 as part of the National Library of Medicine-funded Partners in Information Access contract.The assessment pooled responses from 571 public health workers (73% return rate) representing seventy-two of ninety-five counties (53.4% urban and 46.6% rural) about their information-seeking behaviors, frequency of resources used, computer skills, and level of Internet access. Sixty-four percent of urban and 43% of rural respondents had email access at work and more than 50% of both urban and rural respondents had email at home (N = 289). Approximately 70% of urban and 78% of rural public health officials never or seldom used or needed the Centers for Disease Control (CDC) Website. Frequency data pooled from eleven job categories representing a subgroup of 232 health care professionals showed 72% never or seldom used or needed MEDLINE. Electronic resources used daily or weekly were email, Internet search engines, internal databases and mailing lists, and the Tennessee Department of Health Website.While, due to the small sample size, data cannot be generalized to the larger population, a clear trend of significant barriers to computer and Internet access can be identified across the public health community. This contributes to an overall limited use of existing electronic resources that inhibits evidence-based practice.