Chemical attraction of Dermacentor variabilis ticks parasitic to Peromyscus leucopus based on host body mass and sex

Macroparasites are commonly aggregated on a small subset of a host population. Previous explanations for this aggregation relate to differences in immunocompetence or the degree to which hosts encounter parasites. We propose active tick host choice through chemical attraction as a potential mechanism leading to aggregated tick burdens. We test this hypothesis using a Y-maze olfactometer, comparing chemical attraction responses of larval and nymphal Dermacentor variabilis ticks parasitic to the white-footed mouse, Peromyscus leucopus, as a function of host sex and host body mass. We hypothesized that larger hosts and male hosts would be most attractive to searching ticks, as these hosts commonly have higher tick burdens in the field. Chemical attraction trials were run in the presence and absence of a known tick attractant, host-produced carbon dioxide (CO2). Male hosts and larger hosts were preferred by nymphal D. variabilis in the presence and absence of CO2, whereas larvae had no detectable host preference. The current study suggests that host-produced chemical cues may promote aggregated tick burdens among hosts of a single species based on host body mass and sex. © 2013 Springer Science+Business Media Dordrecht

Modeling the influence of Peromyscus leucopus body mass, sex, and habitat on immature Dermacentor variabilis burden

mmature (larvae and nymph) tick burden on rodents is an important determinant of adult tick population size and understanding infectious disease dynamics. The objective of this research was to build a descriptive model for immature Dermacentor variabilis burden on Peromyscus leucopus. Mice were live-trapped on two permanent grids in an old field and an early successional forest every other month between April and October, 2006-2009. Negative binomial regression was used to examine the association between immature D. variabilis burden and the host related variables of host habitat, body mass, and/or sex. The model containing all three variables had the lowest Akaike\u27s Information Criterion (AIC), corrected AIC (AICc), and greatest AICc weight. Immature D. variabilis burden was positively associated with mice with higher body mass, male mice, and those captured in the field habitat. These data are consistent with studies from other tick-rodent systems and suggest that single factor models do not describe host burden. Variables other than those that are related to the host may also be important in describing the tick burden on rodents. The next step is to examine variables that affect tick development rate and questing behavior. © 2012 The Society for Vector Ecology

Mobile device power management for load flexibility: frequency dynamics and introduction to software aspects

Whereas the layout of electrical networks is reconsidering as a smart grid and the part of renewable energy is increasing, behaviours as sustainability, efficiency and reliability become a need for the current economical and energy contexts. The energy and climate policy from current European Union drivers is an incentive even more significant for this field of research whose results are actually expected. In this context, a better management of power scattered on the grid could emerge as an interesting approach. From the MODEPOMA project, an idea is to manage the energy stored in mobile devices to provide a frequency control as a load aggregator. Among the hierarchy of frequency controls provided to the system as an ancillary service, we focus about the primary reserve whose the purpose is to stop the frequency drop. This master thesis foremost reminds the frequency dynamics of an uncontrolled power system to highlight the need of frequency controls. We introduce the primary frequency control as primary reserve to prevent the frequency drop and stabilize the system frequency to a steady-state value. By this way, we give some basis and a benchmark for the following. Then, we introduce the concept of power management of loads by modelling it and determining applied mechanisms. We prove the possibility to ensure the asymptotic stabilization of the system frequency and check its application through numerical simulations. We take a transmission system operator's perspective regarding to the current standards and possible integrations of the power management of loads. We finally introduce software aspects by defining requirements for an IT platform to implement the power management of loads

Klimaat en identiteit in de Kempen

status: publishe

Klimaatuitdagingen voor de Zuiderkempen

status: publishe

Biological assessment of an eco-touristic project in the tanbi wetland complex, Banjul – the Gambia

info:eu-repo/semantics/nonPublishe

Schoonheid moet betekenis krijgen

A