A LQR-Based Controller with Estimation of Road Bank for Improving Vehicle Lateral and Rollover Stability via Active Suspension.

In this article, a Linear Quadratic Regulator (LQR) lateral stability and rollover controller has been developed including as the main novelty taking into account the road bank angle and using exclusively active suspension for both lateral stability and rollover control. The main problem regarding the road bank is that it cannot be measured by means of on-board sensors. The solution proposed in this article is performing an estimation of this variable using a Kalman filter. In this way, it is possible to distinguish between the road disturbance component and the vehicle's roll angle. The controller's effectiveness has been tested by means of simulations carried out in TruckSim, using an experimentally-validated vehicle model. Lateral load transfer, roll angle, yaw rate and sideslip angle have been analyzed in order to quantify the improvements achieved on the behavior of the vehicle. For that purpose, these variables have been compared with the results obtained from both a vehicle that uses passive suspension and a vehicle using a fuzzy logic controller.

Bacterial distribution and tissue targets following experimental Edwardsiella ictaluri infection in Nile tilapia Oreochromis niloticus.

Edwardsiella ictaluri, a Gram-negative enteric bacterium, is the known etiological agent of enteric septicemia of catfish. In the last few years, different strains have been implicated as the causative agent of mortality events in cultured fish, including Nile tilapia Oreochromis niloticus L. Due to the emergent nature of edwardsiellosis in non-ictalurid fish, little is known about the dynamics of E. ictaluri infection in tilapia. The purpose of this study was to gain a better understanding of the pathogenesis of edwardsiellosis in tilapia by determining the median lethal and infective doses, tissue targets of infection, rate of bacterial dissemination, and the specific tissue response to E. ictaluri following an immersion challenge with bacterial strains recovered from outbreak events in tilapia. In addition to histopathology assessment, the bacterial burdens in several tissues of infected fish were determined over a 2 wk course of infection using quantitative real-time PCR (qPCR). The collected data suggest the cutaneous and oral routes as the main ports of entry for the organism, which later spreads hematogenously throughout the body. Even though histopathological assessment of infected fish revealed involvement of a wide range of tissues, the severity of the necrotizing and granulomatous lesions in the spleen and head kidney, with concomitant high levels of bacterial DNA in these organs determined by qPCR, identifies them as the main targets of infection.

Edwardsiella ictaluri as the causative agent of mortality in cultured Nile tilapia.

Edwardsiella ictaluri was consistently isolated from the spleens, livers, and head kidneys of diseased Nile tilapia Oreochromis niloticus from a farm experiencing mortality events in several culture ponds. We describe the first published outbreak of E. ictaluri-induced edwardsiellosis in Nile tilapia. Pure cultures of the isolated bacteria were characterized both biochemically and molecularly. Biochemical analysis was performed using the API-20E and RapID One systems, and antimicrobial susceptibility was determined by the broth microdilution method. Molecular analysis involved sequencing of the 16S rRNA gene, species-specific real-time polymerase chain reaction (PCR), and PCR-mediated genomic fingerprinting (rep-PCR). Pairwise sequence analysis of the 16S rRNA gene identified the case isolates to be a 100% match to E. ictaluri cultured from channel catfish in the southeastern United States. However, rep-PCR analysis identified the case isolates to be genetically different from representative strains isolated from disease outbreaks in cultured channel catfish in Mississippi. Infectivity challenges (intraperitoneal injection and immersion) demonstrated that a representative E. ictaluri strain isolated from tilapia was pathogenic to naive tilapia, reproducing clinical signs and mortality, thereby establishing Koch's postulates.