Fire Effects on Three Trophic Levels in a Central Arkansas Grassland

We studied the effect of a late growing-season fire on the plant and foliar arthropod communities in a naturally occurring grassland. In central Arkansas, these grasslands are common on south-facing slopes where shallow soils and hot/dry weather conditions during the summer cannot support the growth of a forest community. Patches of grassland were burned in the autumn (4 November, late growing season), often the time of natural fires in Arkansas, and compared to unburned areas. Fire increased the biomass of forbs and decreased the biomass of grasses, although overall biomass was not different between treatments. Among the foliar arthropods, herbivores were significantly reduced by burning, especially the Homoptera. Carnivorous arthropods as a whole were not affected by burning, although spiders showed a small but significant reduction. The response of arthropods to fire occurred almost one year after the burn, showing that fire effects can be delayed for a substantial period of time. This experiment shows that fire occurring during the natural burning period in Arkansas can have substantial effects on grasslands communities. The response of plants in Arkansas is similar to that of plants in nearby grasslands on the Great Plains and southeastern United States which also show a great increase in forbs under late growing season burning regimes. The changes seen in this experiment demonstrate that the suppression of fire by humans has probably modified the structure of Arkansas grasslands. With the increasing use of fire as a management tool in Arkansas, changes to grassland systems are likely to be profound

Expert consensus on an in vitro approach to assess pulmonary fibrogenic potential of aerosolized nanomaterials

The increasing use of multi-walled carbon nanotubes (MWCNTs) in consumer products and their potential to induce adverse lung effects following inhalation has lead to much interest in better understanding the hazard associated with these nanomaterials (NMs). While the current regulatory requirement for substances of concern, such as MWCNTs, in many jurisdictions is a 90-day rodent inhalation test, the monetary, ethical, and scientific concerns associated with this test led an international expert group to convene in Washington, DC, USA, to discuss alternative approaches to evaluate the inhalation toxicity of MWCNTs. Pulmonary fibrosis was identified as a key adverse outcome linked to MWCNT exposure, and recommendations were made on the design of an in vitro assay that is predictive of the fibrotic potential of MWCNTs. While fibrosis takes weeks or months to develop in vivo, an in vitro test system may more rapidly predict fibrogenic potential by monitoring pro-fibrotic mediators (e.g., cytokines and growth factors). Therefore, the workshop discussions focused on the necessary specifications related to the development and evaluation of such an in vitro system. Recommendations were made for designing a system using lung-relevant cells co-cultured at the air–liquid interface to assess the pro-fibrogenic potential of aerosolized MWCNTs, while considering human-relevant dosimetry and NM life cycle transformations. The workshop discussions provided the fundamental design components of an air–liquid interface in vitro test system that will be subsequently expanded to the development of an alternative testing strategy to predict pulmonary toxicity and to generate data that will enable effective risk assessment of NMs

Technology Transfer From Military Applications to Intelligent Vehicle Highway Systems

Since the conclusion of World War II, the U.S. government has developed a massive sponsorship of scientific research activities, primarily to advance military goals. This financial support of both private companies and national labs has constituted a closet industrial policy whose usefulness and efficiency is now coming into question. The end of the Cold War has produced a consensus in the United States that military spending must be cut dramatically. These reductions will mean loss of revenue for national labs and for military contractors, many of whom are structurally dependent on their primary customer - the Department of Defense. Different private companies will respond to these challenges in different ways, but the most prudent will seek to convert their technological competencies into new products for new markets. Intelligent Highway Vehicle Systems (IVHS), which uses sensors, communications and information management to increase the capacity of transportation systems, is one possibility for conversion. IVHS shares technological and structural similarities with advanced weapons production. In this paper, 24 private companies and six national laboratories are examined. Each of these companies are both prominent recipients of DoD contracts and interested in IVHS. For each of the private companies, the following factors are examined: the current level of diversification in non-military products technical competency in transferrable technologies experience in !VHS-related commercial markets Each of the six national laboratories are profiled. Finally, predictions are given for ever-changing political climate of technology conversion, particularly with respect to the federal support IVHS is likely to receive in the future

Relationship of Carbapenem Restriction in 22 University Teaching Hospitals to Carbapenem Use and Carbapenem-Resistant Pseudomonas aeruginosa▿

Many hospital antimicrobial stewardship programs restrict the availability of selected drugs by requiring prior approval. Carbapenems may be among the restricted drugs, but it is unclear if hospitals that restrict availability actually use fewer carbapenems than hospitals that do not restrict use. Nor is it clear if restriction is related to resistance. We evaluated the relationship between carbapenem restriction and the volume of carbapenem use and both the incidence rate and proportion of carbapenem-resistant Pseudomonas aeruginosa isolates from 2002 through 2006 in a retrospective, longitudinal, multicenter analysis among a consortium of academic health centers. Carbapenem use was measured from billing records as days of therapy per 1,000 patient days. Hospital antibiograms were used to determine both the incidence rate and proportion of carbapenem-resistant P. aeruginosa isolates. A survey inquired about restriction policies for antibiotics, including carbapenems. General linear mixed models were used to examine study outcomes. Among 22 hospitals with sufficient data for analysis, overall carbapenem use increased significantly over the 5 years of study (P < 0.0001), although overall carbapenem resistance in P. aeruginosa did not change. Hospitals that restricted carbapenems (n = 8; 36%) used significantly fewer carbapenems (P = 0.04) and reported lower incidence rates of carbapenem-resistant P. aeruginosa (P = 0.01) for all study years. Fluoroquinolone use was a potential confounder of these relationships, but hospitals that restricted carbapenems actually used fewer fluoroquinolones than those that did not. Restriction of carbapenems is associated with both lower use and lower incidence rates of carbapenem resistance in P. aeruginosa

Identifying hospital antimicrobial resistance targets via robust ranking

<p>We develop a robust ranking procedure to uncover trends in variation in antibiotic resistance (AR) rates across hospitals for some antibiotic-bacterium pairs over several years. We illustrate how the method can be used to detect potentially dangerous trends and to direct attention to hospitals’ management practices. A robust method is indicated because some unusual reported resistance rates may be due to measurement protocol differences and not any real difference in AR rates. Our proposed method is less sensitive to outlier observations than other robust methods. The application on real AR data shows how a dangerous trend in a particular AR rate would be detected. Our results indicate the potential benefits of systematic AR rate collection and AR reporting systems across hospitals.</p