While other navigational mechanisms (e.g. path integration) are well studied, the question of how ants extract reliable visual features from a complex visual scene is still largely open. This paper explores the assumption that the upper outline of ground objects formed against the sky, i.e. the skyline, provides sufficient information for visual navigation. We constructed a virtual model of the ant’s environment. In the virtual environment, panoramic images were recorded and adapted to the resolution of the desert ant’s complex eye. From these images either a skyline code or a pixel-based intensity code were extracted.

Further, two homing algorithms were implemented, a modified version of the average landmark vector (ALV) model (Lambrinos et al. Robot Auton Syst 30:39-64, 2000) and a gradient ascent method. Results show less spatial aliasing for click here skyline coding and best homing performance for ALV homing based on skyline codes. This supports the assumption of skyline coding in visual homing

of desert ants and allows novel approaches to technical outdoor navigation.”
“The pharmacogenetics of methotrexate (MTX) was investigated in a large cohort of pediatric patients with acute lymphoblastic leukemia (ALL). Four hundred ninety-nine children with ALL from the ALL-BFM (Berlin-Frankfurt-Munster) 2000 trial who received 1996 courses of MTX at 5 g/m(2) were PD-1/PD-L1 activation genotyped for 8 single nucleotide polymorphisms in 5 candidate genes of the MTX/folate pathway. Patients’ MTX pharmacokinetics, MTX toxicities, and outcomes were correlated with the genotypes. The interindividual variability in MTX kinetics had a substantial genetic component between 68% and 75%. The SLCO1B1 rs4149056 variant was significantly associated with MTX kinetics. In a multiple regression model, MTX area under the concentration time curve (AUC)(0-48h) increased by 26% (P < .001) per SLCO1B1 rs4149056 C allele. MTX AUC(0-48h) was a significant predictor

of overall toxic adverse events during MTX courses (R-2 = 0.043; P < .001), whereas the thymidylate synthase rs34743033 tandem repeat polymorphism was predictive of stomatitis (R-2 = 0.018; P = .009), a frequent AZD6094 in vitro side effect of high-dose MTX. Multiple Cox regression analyses revealed an association of minimal residual disease (hazard ratio 7.3; P < .001) and methylenetetrahydrofolate reductase rs1801131 (hazard ratio 3.1; P=.015) with event-free survival in the ALL-BFM 2000 study population. Genetic variations substantially influence the kinetics and response to high-dose MTX therapy in childhood ALL.”
“Vesicular monoamine transporter 2 (VMAT2) is expressed in pancreatic beta cells and has recently been proposed as a target for measurement of beta cell mass in vivo.