How can an invasive grass affect fire behavior in a tropical savanna? A community and individual plant level approach

Some invasive grasses have been reported to change fire behavior in invaded plant communities. Urochloa brizantha is an aggressive invasive grass in the Brazilian Cerrado, an ecosystem where fire is a common disturbance. We investigated the effects of U. brizantha on fire behavior in an open Cerrado physiognomy in Central Brazil. Using experimental burnings we compared fire behavior at both the community and the individual plant level in invaded (UJ) and non-invaded (NJ) areas burned in July. We also assessed the effect of fire season in invaded areas by comparing July (UJ) and October (UO) burnings. We evaluated the following variables: fuel load, fuel moisture, combustion efficiency, maximum fire temperature, flame height, and fire intensity. Additionally, we evaluated the temperatures reached under invasive and native grass tussocks in both seasons. Fuel load, combustion efficiency, and fire intensity were higher in NJ than in UJ, whilst flame height showed the opposite trend. Fuel amount and fire intensity were higher in October than in July. At the individual plant level, U. brizantha moisture was higher than that of native species, however, temperatures reaching ≥600 °C at ground level were more frequent under U. brizantha tussocks than under native grasses. At the community level, the invasive grass modified fire behavior towards lower intensity, lower burning efficiency, and higher flame height. These results provide essential information for the planning of prescribed burnings in invaded Cerrado areas.

SILVER NANOPARTICLES AND THE PLANT-ASSOCIATING ABILITIES OF RHIZOBIACEAE BACTERIA

The use of nanoparticle technology in consumer products has been increasing due to their broad-spectrum antimicrobial properties. Specifically, silver nanoparticles (AgNPs) can demonstrate distinct physiochemical properties compared to bulk silver, including a large surface area to volume ratio that allows for higher reactivity with bacterial cell surfaces. AgNPs are being released into the environment, including soil ecosystems through various pathways such as points of production or during disposal of silver-containing products. This raises the concern about the potential impact on beneficial soil bacteria and their surrounding ecosystems. Members of the Rhizobiaceae family play important roles in nutrient cycling and contribute to overall soil fertility and the experiments in this thesis address the potential for AgNP-mediated toxicity on these plant-associating bacteria. Respiration analysis of Bradyrhizobium japonicum, Azospirillum brasilense, and Agrobacterium tumefaciens has revealed that AgNPs can negatively impact the growth and survival of these bacterial species, with B. japonicum being the most susceptible. Additionally, swimming motility assays using B. japonicum showed a significant decrease in colony diameter when treated with AgNPs (50 ppm). A significant decrease in root colonization of Triticum aestivum roots by A. brasilense was observed as AgNP treatment concentrations increased. Although some of the experiments could not be completed, taken together, these experiments and the research reported herein highlights the potential toxicological effects of AgNPs on bacterial species vital to the growth and health of agriculturally important crops.

Odor and corrosion control in sanitary sewerage systems and treatment plants : design manual.

Mode of access: Internet.

Conventional and advanced sewer design concepts for dual purpose flood and pollution control : a preliminary case study, Elizabeth, New Jersey /

Mode of access: Internet.

Maintaining and donning the self-contained breathing apparatus (SCBA) /

"April 1982."

Earth and aggregate surfacing design guide for low volume roads /

"September 1996."

Experimental and formal language design applied to control constructs for interactive computing /

Vita.

Noyo River and Harbor, California, design for wave and surge protection : coastal model investigation /

"September 1988."

Noyo River and Harbor, California design for wave protection supplemental tests : coastal model investigation /

"December 1989."

Onsight wastewater treatment and disposal systems : design manual /

"October 1980."

Baroque and romantic stage design.

Bibliography: p. 22-24.

Examples and ideas to stimulate and improve the design, art & architecture of airports /

Includes bibliographical references.

Technology and manpower in design and drafting, 1965-75.

Bibliographical footnotes.

A study and proposed re-design of the materials handling process for the Freeville Concrete Products Co., of Factory Street, Freeville, N. Y.

"Study made for Methods Engineering, Course 3262, Cornell University, for term paper, Fall, 1956."