This symposium was dedicated to science opportunities with the VLT. All major areas of astronomical research were discussed in the plenary sessions, ranging from where we stand in cosmology to the new frontiers in the solar system. The workshops published in this volume focussed on different ways of finding clusters of galaxies at high redshift, on gravitational lensing by distant compact clusters, on the use of stellar populations as distance, age or abundance indicators, and on the extraordinary progress made in the discovery of extrasolar planets. This book affords a glimpse of what will be at the center of astrophysical research in the forthcoming decade. It is addressed to researchers and graduate students.

This is an exhaustive review of our theoretical and observational knowledge of gravitational lensing 10 years after the discovery of the first lensed quasar, Q0957+561. Gravitational optics, optical, infrared, and radio observations of quasar-lens candidates, microlensing, arcs in clusters of galaxies, and radio rings are presented. In particular, the continuing survey of quasar-lens candidates, the new measurement of the time delay in 0957+561, the suspended microlensing effect through the galaxy 2237+030, as well as the discovery of new arcs and the measurement of new redshifts for two of them are presented. Numerous papers on the modelling of arcs and rings show how it should be possible to probe dark matter with these unexpected gravitational telescopes. Finally, tables summarize all the lens candidates we know today.

This book gathers a selection of peer-reviewed papers presented at the International Conference on Operations Research (OR 2018), which was held at the Free University of Brussels, Belgium on September 12 - 14, 2018, and was jointly organized by the German Operations Research Society (GOR) and the Belgian Operational Research Society (ORBEL). 575 scientists, practitioners and students from mathematics, computer science, business/economics and related fields attended the conference and presented more than 400 papers in parallel topic streams, as well as special award sessions. The respective papers discuss classical mathematical optimization, statistics and simulation techniques. These are complemented by computer science methods, and by tools for processing data, designing and implementing information systems. The book also examines recent advances in information technology, which allow big data volumes to be processed and enable real-time predictive and prescriptive business analytics to drive decisions and actions. Lastly, it includes problems modeled and treated while taking into account uncertainty, risk management, behavioral issues, etc.