We propose a generalization of the Bjorken in-out Ansatz for fluid trajectories, which, when applied to the 1+1 hydrodynamic equations, generates a one-parameter family of analytic solutions interpolating between the boost-invariant Bjorken picture and the non-boost-invariant one by Landau. This parameter characterizes the proper-time scale when the fluid velocities approach the in-out Ansatz. We discuss the resulting rapidity distribution of entropy for various freeze-out conditions and compare it with the original Bjorken and Landau results.

Particle production in $\mathrm{Au}\text{−}\mathrm{Au}$, $\mathrm{Cu}\text{−}\mathrm{Cu}$, $d$-Au, and $p\text{−}p$ collisions at 200 GeV c.m. energy are analyzed in the wounded quark-diquark model. Existing data are well reproduced. Emission functions of wounded and unwounded constituents are determined. Implications for the collective evolution of the system are discussed.

It is proposed that soft particle production in hadronic collisions is dominated by multiple gluon exchanges between partons from the colliding hadrons, followed by radiation of hadronic clusters from the coloured partons distributed uniformly in rapidity. This explains naturally two dominant features of the data: (a) the linear increase of rapidity spectra in the regions of limiting fragmentation and, (b) the proportionality between the increasing width of the limiting fragmentation region and the height of the central plateau.

The paper concerns research related to the European project CIRAS and presents a validation experiment with the use of a risk management tool adapted for critical infrastructures. The project context and state of the art are discussed. The adaptation of the risk management tool is performed according to previously elaborated requirements which consider interdependencies, cause-consequences analysis, risk measures and risk register implementation. A novel structured risk management method was proposed how to deal with internal and external impacts of a hazardous event which occurred in the given CI. The method is embedded into the critical infrastructure resilience process. These requirements can be implemented on the ready-to-use software platform for further experiments. The experimentation results are used as the input for CIRAS. The discussed tool can be applied as the risk reduction component in the CIRAS Tool, and the validation process presented here is the basis to elaborate two project use cases.

The possibility that particle production in high-energy collisions is a result of two asymmetric hydrodynamic flows is investigated using the Khalatnikov form of the (1+1)-dimensional approximation of hydrodynamic equations. The general solution is discussed and applied to the physically appealing ``generalized in-out cascade'' where the space-time and energy-momentum rapidities are equal at initial temperature but boost invariance is not imposed. It is demonstrated that the two-bump structure of the entropy density, characteristic of the asymmetric input, changes easily into a single broad maximum compatible with data on particle production in symmetric processes. A possible microscopic QCD interpretation of asymmetric hydrodynamics is proposed.