Bothrops asper is the species that induces the highest incidence of snakebite envenomation in southern Mexico, Central America and parts of northern South America. The intraspecies variability in HPLC profile and toxicological activities between the venoms from specimens collected in Mexico (Veracruz) and Costa Rica (Caribbean and Pacific populations) was investigated, as well as the cross-neutralization by antivenoms manufactured in these countries. Venoms differ in their HPLC profiles and in their toxicity, since venom from Mexican population showed higher lethal and defibrinogenating activities, whereas those from Costa Rica showed higher hemorrhagic and in vitro coagulant activities. In general, antivenoms were more effective in the neutralization of homologous venoms. Overall, both antivenoms effectively neutralized the various toxic effects of venoms from the two populations of B. asper. However, antivenom raised against venom from Costa Rican specimens showed a higher efficacy in the neutralization of defibrinogenating and coagulant activities, thus highlighting immunochemical differences in the toxins responsible for these effects associated with hemostatic disturbances in snakebite envenoming. These observations illustrate how intraspecies venom variation may influence antivenom neutralizing profile.
It is recognized that disturbance rejection is much more important than set-point tracking for many process control applications, leading set-point tracking to a secondary level of interest. In this paper a proposal for robust tuning of PI/PID controllers designed under the direct synthesis for load disturbance (DS-d) approach is presented. As with the IMC-like approaches, the resulting DS-d tunings are expressed in terms of a unique parameter that determines the desired speed of response of the regulatory behavior. Even at first sight it may seem quite simple, there is no known guide on how to select such parameter in order to achieve some desired robustness. As it will be shown, for some process dynamics, this selection is not as simple as it may seem. Tuning expressions for the most common types of process models are provided such that the closed loop time constant is the fastest one that allows to reach the desired robustness. Simulation examples show the application of the suggested tuning.
