Frankfurt Institute for Advanced Studies

About: Frankfurt Institute for Advanced Studies is a facility organization based out in Frankfurt am Main, Germany. It is known for research contribution in the topics: Baryon & Quark–gluon plasma. The organization has 798 authors who have published 2733 publications receiving 82799 citations. The organization is also known as: FIAS.

High-Resolution Epidemic Simulation Using Within-Host Infection and Contact Data

Abstract: Recent epidemics have entailed global discussions on revamping epidemic control and prevention approaches. A general consensus is that all sources of data should be embraced to improve epidemic preparedness. As a disease transmission is inherently governed by individual-level responses, pathogen dynamics within infected hosts posit high potentials to inform population-level phenomena. We propose a multiscale approach showing that individual dynamics were able to reproduce population-level observations. Using experimental data, we formulated mathematical models of pathogen infection dynamics from which we simulated mechanistically its transmission parameters. The models were then embedded in our implementation of an age-specific contact network that allows to express individual differences relevant to the transmission processes. This approach is illustrated with an example of Ebola virus (EBOV). The results showed that a within-host infection model can reproduce EBOV’s transmission parameters obtained from population data. At the same time, population age-structure, contact distribution and patterns can be expressed using network generating algorithm. This framework opens a vast opportunity to investigate individual roles of factors involved in the epidemic processes. Estimating EBOV’s reproduction number revealed a heterogeneous pattern among age-groups, prompting cautions on estimates unadjusted for contact pattern. Assessments of mass vaccination strategies showed that vaccination conducted in a time window from five months before to one week after the start of an epidemic appeared to strongly reduce epidemic size. Noticeably, compared to a non-intervention scenario, a low critical vaccination coverage of 33% cannot ensure epidemic extinction but could reduce the number of cases by ten to hundred times as well as lessen the case-fatality rate. Experimental data on the within-host infection have been able to capture upfront key transmission parameters of a pathogen; the applications of this approach will give us more time to prepare for potential epidemics. The population of interest in epidemic assessments could be modelled with an age-specific contact network without exhaustive amount of data. Further assessments and adaptations for different pathogens and scenarios to explore multilevel aspects in infectious diseases epidemics are underway.

Giant Nuclear Systems of Molecular Type

Abstract: Low-energy dynamics of heavy nuclear systems is studied within the extended version of the two-center shell model and Langevin type equations of motion. The shell effects lead to the appearance of local minima and deep valleys on the multi-dimensional potential energy surface. It is shown that the local minima on the fission path of a heavy nucleus—so called isomeric states—are nothing else but the two-cluster configurations with magic or semi-magic cores surrounded with a certain number of shared nucleons. Clustering phenomena caused by the shell effects play an important role also in low-energy dynamics of heavy nuclear systems. Fission and quasi-fission are the well-known processes of such kind discussed in the paper. We found that in low-energy damped multi-nucleon transfer reactions the shell effects may significantly enhance the yield of new heavy neutron-rich nuclei located in the unexplored “north-east” area of the nuclear map which is important for astrophysical nucleosynthesis. A possibility for the production of long-living neutron-rich superheavy nuclei in collisions of actinide ions (such as 238U + 248Cm) is another important finding. In these reactions a large mass and charge transfer due to the inverse (anti-symmetrized) quasi-fission process is significantly enhanced by the clustering process with formation of closed shell nuclei around Z = 82 and N = 126. In many such collisions the lifetime of a composite system consisting of two touching actinide nuclei turns out to be rather long (> 10−20S). This time delay is sufficient for the observation of the line structure in spontaneous e + e − production from the supercritical electric field of a giant quasi-atom—a fundamental QED process not observed yet experimentally. In addition, this giant nuclear molecule might undergo to a three-body clusterization (ternary quasi-fission) with formation of two heavy lead-like fragments in the exit channel. The “true ternary fission” is also possible for superheavy nuclei‘

Anisotropic flow in transport + hydrodynamics hybrid approaches

Abstract: This contribution to the focus issue covers anisotropic flow in hybrid approaches. The historical development of hybrid approaches and their impact on the interpretation of flow measurements is reviewed. The major ingredients of a hybrid approach and the transition criteria between transport and hydrodynamics are discussed. The results for anisotropic flow in (event-by-event) hybrid approaches are presented. Some hybrid approaches rely on hadronic transport for the late stages for the reaction (so called afterburner) and others employ transport approaches for the early non-equilibrium evolution. In addition, there are ‘full’ hybrid calculations where a fluid evolution is dynamically embedded in a transport simulation. After demonstrating the success of hybrid approaches at high Relativistic Heavy Ion Collider and Large Hadron Collider energies, existing hybrid caluclations for collective flow observables at lower beam energies are discussed and remaining challenges outlined.