2018 Impact factor 2.481
Hadrons and Nuclei

EPJ B Highlight - Entropy explains RNA diffusion rates in cells

RNA molecules diffuse in characteristic ways. https://commons.wikimedia.org/ wiki/File:50S-subunit_of_the_ ribosome_3CC2.png

Mathematical analysis reveals that the exponential patterns in RNA diffusion rates linked to small-scale diffusive behaviours

Recent studies have revealed that within cells of both yeast and bacteria, the rates of diffusion of RNA proteins – complex molecules that convey important information throughout the cell – are distributed in characteristic exponential patterns. As it turns out, these patterns display the highest possible degree of disorder, or ‘entropy’, of all possible diffusion processes within the cell. In new research published in EPJ B, Yuichi Itto at Aichi Institute of Technology in Japan explores this behaviour further by zooming in to study local fluctuations in the diffusion rates of RNA proteins. By associating these small-scale diffusion rates with time-varying values for entropy, he finds that the rates of change of entropy in certain time intervals are larger in areas with higher RNA diffusion rates.

Read more...

EPJ B Highlight - Spinning towards robust microwave generation on the nano scale

Snapshots of an ensemble of 100 spin-torque oscillators at different points in time, plotting values of inductance (L) against capacitance (C). Red dots show individual oscillators.

New study explains why it is not possible to couple nano-scale microwave generators known as spin-torque oscillators together in series to generate a macroscopic strength signal

Spin-torque oscillators (STOs) are nanoscale devices that generate microwaves using changes in magnetic field direction, but those produced by any individual device are too weak for practical applications. Physicists have attempted - and, to date, consistently failed - to produce reliable microwave fields by coupling large ensembles. Michael Zaks from Humboldt University of Berlin and Arkady Pikovsky from the University of Potsdam in Germany have now shown why connecting these devices in series cannot succeed, and, at the same time, suggested other paths to explore. Their work was recently published in EPJ B.

Read more...

EPJ B Highlight - New insights into the early stages of creep deformation

Varying strain patterns during creep deformation.

Computer simulations show that the evolution of material structures during creep deformation can modify material properties.

The properties of many materials can change permanently when they are pushed beyond their limits. When a given material is subjected to a force, or ‘load’, which is stronger than a certain limit, it can become so deformed that it won’t return to its original shape, even after the load is removed. However, heavy loads aren’t strictly necessary to deform materials irreversibly; this can also occur if they are subjected to lighter loads over long periods of time, allowing a slow process called ‘creep’ to take place. Physicists have understood for some time that this behaviour involves sequences of small, sudden deformations, but until now, they have lacked a full understanding of how creep deformation affects material properties over time. In new research published in EPJ B, Michael Zaiser and David Castellanos at the University of Erlangen-Nuremberg in Germany analysed the characteristic ways in which material structures evolve during the early stages of creep deformation.

Read more...

EPJ B Highlight - Spread-changing orders and deletions affect stock prices

Trade orders strongly influence stock prices. Photo by M. B. M. on https://unsplash.com/photos/ ZzOa5G8hSPI.

A new analysis of the bid-ask spread of stock prices reveals that placements and deletions of trade orders can affect stock prices as much as trades themselves

The first rule on the stock market is to buy low and sell high. Economists are well aware of how this behaviour changes the prices of stocks, but in reality, trades alone don’t tell the whole story. Parties like banks and insurance companies rarely trade stocks themselves; instead, they place orders for traders to do so on their behalf, which can be canceled at any time if they are no longer interested. The amount payed by those placing orders is affected by a highly variable quantity called the bid-ask ‘spread’ – the difference between the price initially quoted for a stock, and the final bidding price. In a new study published in EPJ B, Stephan Grimm and Thomas Guhr from Duisburg-Essen University in Germany compare the influences that three price-changing events have on these spread changes. Their work sheds new light on the intricate inner workings of the stock market.

Read more...

EPJ B Review Article - Micromagnetics and Spintronics: Models and Numerical Methods

Computational micromagnetics has become an indispensable tool for the theoretical investigation of magnetic structures. Classical micromagnetics has been successfully applied to a wide range of applications including magnetic storage media, magnetic sensors, permanent magnets and more. The recent development of spintronics devices has led to various extensions to the micromagnetic model in order to account for spin-transport effects. Now, Claas Abert of the University of Vienna has prepared a comprehensive Review Article on the subject for EPJ B, aiming to provide an overview of the analytical micromagnetic model as well as its numerical implementation. The main focus is put on the integration of spin-transport effects with classical micromagnetics.

Read more...

EPJ B Highlight - How to stop diseases and forest fires from spreading

When the population approaches a certain level of heterogeneity, the infection slows.

A new model, published in EPJ B and exploring how epidemics spread, could help prevent infections and forest fires from getting out of hand

Recently, epidemics like measles have been spreading due to the lack of vaccinations, and forest fires have become increasingly frequent due to climate change. Understanding how both these things spread, and how to stop them, is more important than ever. Now, two researchers from the National Scientific and Technical Research Council in Bariloche, Argentina, have studied the way epidemics spread in heterogeneous populations. Their findings were recently published in European Physical Journal B.

Read more...

EPJ B Highlight - Inhibitory neurons have two types of impact on brain oscillations

The emergence of synchronization with excitatory and inhibitory neurons.

A certain type of neuron, called inhibitory neurons, can have two types of overall effect on oscillations in the brain

Studying the brain involves measuring the activity of billions of individual brain cells called neurons. Consequently, many brain measurement techniques produce data that is averaged to reflect the activity of large populations of these neurons. If all of the neurons are behaving differently, this will average out. But, when the behaviour of individual neurons is synchronized, it produces clearly visible oscillations.

Synchronisation is important to understanding how neurons behave, which is particularly relevant with regard to brain diseases like Alzheimer’s, epilepsy and Parkinson’s. Now, a group of researchers from the Institute of Computational Physics and Complex Systems at Lanzhou University, China, has used a combination of two computer models to study the ways different kinds of neurons can impact synchronisation. The study is published in the European Physical Journal B.

Read more...

EPJB Colloquium - Complex band-structure analysis and topological physics of Majorana nanowires

In this new Colloquium article published in EPJ B, Javier Osca (IMEC and KU Leuven, Belgium) and Llorenç Serra (IFISC and Departament de Física, Universitat de les Illes Balears, Palma, Spain) review applications of complex band structure theory to describe Majorana states in nanowires and nanowire junctions. The dimensionality of the considered wires is gradually increased, from strictly 1D to quasi-1D with one and two transverse dimensions.

Read more...

EPJ B Highlight - Magnetic nanoparticles can 'burn' cancer cells

Stock market prediction models.

Magnetic hyperthermia is still a highly experimental cancer treatment, but new research shows that the therapy is tunable

Unfortunately, cancer isn’t simply a single disease, and some types, like pancreas, brain or liver tumours, are still difficult to treat with chemotherapy, radiation therapy or surgery, leading to low survival rates for patients. Thankfully, new therapies are emerging, like therapeutic hyperthermia, which heats tumours by firing nanoparticles into tumour cells. In a new study published in EPJ B, Angl Apostolova from the University of Architecture, Civil Engineering and Geodesy in Sofia, Bulgaria and colleagues show that tumour cells’ specific absorption rate of destructive heat depends on the diameter of the nanoparticles and the composition of the magnetic material used to deliver the heat to the tumour.

Read more...

EPJ B Colloquium - Cooperative magnetic phenomena in artificial spin systems: spin liquids, Coulomb phase and fragmentation of magnetism

Two-dimensional arrays of interacting magnetic nanostructures offer a remarkable playground for simulating, experimentally, lattice spin models. Initially designed to capture the low-energy physics of highly frustrated magnets, they quickly became a lab-on-chip platform to investigate cooperative magnetic phenomena often associated with classical frustrated magnetism.

This Colloquium paper from Nicolas Rougemaille and Benjamin Canals at the Institut NEEL (Univ. Grenoble, CNRS, France) reviews the many-body physics which can be visualized, directly in real space, through the magnetic imaging of artificial arrays of magnetic nanostructures. Particular attention is paid to classical spin liquid states, magnetic Coulomb phases and magnetic moment fragmentation. Other phenomena, such as complex magnetic ordering, charge crystallization and monopole-like excitations, are also described in light of the recent advances in the field.

Read more...

Editors-in-Chief
David Blaschke, Thomas Duguet and Maria Jose Garcia Borge
Thank you once more for your very careful and excellent editing.

Vicente Vento, Departamento de Fisica Teorica, Universidad de Valencia, Spain

ISSN (Print Edition): 1434-6001
ISSN (Electronic Edition): 1434-601X

© Società Italiana di Fisica and
Springer-Verlag