General, PDB-based collective variables for protein folding

New, automated forms of data-analysis are required in order to understand the high-dimensional trajectories that are obtained from molecular dynamics simulations on proteins. Dimensionality reduction algorithms are particularly appealing in this regard as they allow one to construct unbiased, low-dimensional representations of the trajectory using only the information encoded in the trajectory. The downside of this approach is that different sets of coordinates are required for each different chemical systems under study precisely because the coordinates are constructed using information from the trajectory. In this paper we show how one can resolve this problem by using the sketch-map algorithm that we recently proposed to construct a low-dimensional representation of the structures contained in the protein data bank (PDB). We show that the resulting coordinates are as useful for analysing trajectory data as coordinates constructed using landmark configurations taken from the trajectory and that these coordinates can thus be used for understanding protein folding across a range of systems.

Collective synchrony increases prosociality towards non-performers and out-group members

Previous research has found that behavioural synchrony between people leads to greater prosocial tendencies towards co-performers. In this study we investigated the scope of this prosocial effect: does it extend beyond the performance group to an extended in-group (extended parochial prosociality) or even to other people in general (generalized prosociality)? Participants performed a simple rhythmic movement either in time (synchrony condition) or out of time (asynchrony condition) with each other. Before and during the rhythmic movement, participants were exposed to a prime that made salient an extended in-group identity. After the task, half the participants had the opportunity to help an extended in-group member; the other half had the opportunity to help an out-group member. We found a main effect of our synchrony manipulation across both help targets suggesting that the prosocial effects of synchrony extend to non-performers. Furthermore, there was a significantly higher proportion of participants willing to help an out-group member after moving collectively in synchrony. This study shows that under certain intergroup contexts synchrony can lead to generalized prosociality with performers displaying greater prosociality even towards out-group members.

Non-Gaussian distribution of collective operators in quantum spin chains

We numerically analyse the behavior of the full distribution of collective observables in quantum spin chains. While most of previous studies of quantum critical phenomena are limited to the first moments, here we demonstrate how quantum fluctuations at criticality lead to highly non-Gaussian distributions. Interestingly, we show that the distributions for different system sizes collapse on thesame curve after scaling for a wide range of transitions: first and second order quantum transitions and transitions of the Berezinskii–Kosterlitz–Thouless type. We propose and analyse the feasibility of an experimental reconstruction of the distribution using light–matter interfaces for atoms in optical lattices or in optical resonators.