Efficacy of chemical repellents against Otobius megnini (Acari: Argasidae) and three species of ixodid ticks.

Otobius megnini (Dugès), often referred to as the ear tick or spinose ear tick, is a one-host tick native to the southwestern United States and Mexico. Infestations of this species can cause severe irritation and may affect breeding behavior in the host. Although chemical repellents are commonly used as an alternative approach to conventional arthropod vector control, information on repellency against O. megnini is lacking. This study compared repellency of ammonia, BioUD(®), 98.25% DEET, garlic pepper tea, permanone, and pyrethrin with piperonyl butoxide, against larvae stages of O. megnini, Amblyomma americanum (L.), Dermacentor variabilis (Say), and Rhipicephalus sanguineus (Latreille). To test for repellency, tick movement was recorded at 30 s intervals for five min after introduction to a partially treated piece of filter paper. Results showed larvae of O. megnini exhibited less aversion to the chemicals tested when compared to the other tick species.

Combining GIS with fuzzy multicriteria decision-making for landfill siting in a fast-growing urban region.

Landfill siting is a difficult, complex, tedious, and protracted process requiring evaluation of many different criteria. This paper presents a fuzzy multicriteria decision analysis alongside with a geospatial analysis for the selection of landfill sites. It employs a two-stage analysis synergistically to form a spatial decision support system (SDSS) for waste management in a fast-growing urban region, south Texas. The first-stage analysis makes use of the thematic maps in Geographical information system (GIS) in conjunction with environmental, biophysical, ecological, and socioeconomic variables leading to support the second-stage analysis using the fuzzy multicriteria decision-making (FMCDM) as a tool. It differs from the conventional methods of integrating GIS with MCDM for landfill selection because the approach follows two sequential steps rather than a full-integrated scheme. The case study was made for the city of Harlingen in south Texas, which is rapidly evolving into a large urban area due to its vantage position near the US-Mexico borderlands. The purpose of GIS was to perform an initial screening process to eliminate unsuitable land followed by utilization of FMCDM method to identify the most suitable site using the information provided by the regional experts with reference to five chosen criteria. Research findings show that the proposed SDSS may aid in recognizing the pros and cons of potential areas for the localization of landfill sites in any study region. Based on initial GIS screening and final FMCDM assessment, "site 1" was selected as the most suitable site for the new landfill in the suburban area of the City of Harlingen. Sensitivity analysis was performed using Monte Carlo simulation where the decision weights associated with all criteria were varied to investigate their relative impacts on the rank ordering of the potential sites in the second stage. Despite variations of the decision weights within a range of 20%, it shows that "site 1" remains its comparative advantage in the final site selection process.