News

EPJ E Highlight - How do vertebrates take on their form?

Details: Published on 16 February 2015

alt — Modeling of the fold formation mechanism. A sheet of rubber on which a (stiffer) paper label is stuck buckles along the boundary between the stiff zone and the soft zone when it is stretched. This reproduces the formation of folds along the boundaries between cellular domains. © VF-CNRS-MSC/EDP Sciences-SIF-Springer SBM

A simple physical mechanism that can be assimilated to folding, or buckling, means that an unformed mass of cells can change in a single step into an embryo organized as a typical vertebrate. This is the main conclusion of work by a team involving physicists from the Laboratoire Matière et Systèmes Complexes (CNRS/Université Paris Diderot) and a biologist from the Laboratoire de Biologie du Développement (CNRS/UPMC).

Thanks to microscopic observations and micromechanical experiments, the scientists have discovered that the pattern that guides this folding is present from the early stages of development. The folds that will give a final shape to the animal form along the boundaries between cell territories with different properties. This work has shed light on the mechanism for the formation of vertebrates and thus how they appeared during evolution. These findings have just been published in EPJ E.

EPJ D Highlight - Novel high-power microwave generator

Details: Published on 11 February 2015

Axial profile of the axisymmetric semi-circular structure to be used as a slow wave structure in backward wave oscillators.

A new study explores the viability of a novel structure to be used as a component of a high-power microwave source, designed to transfer energy to targets via ultra-high-frequency radio waves

High-power microwaves are frequently used in civil applications, such as radar and communication systems, heating and current drive of plasmas in fusion devices, and acceleration in high-energy linear colliders. They can also be used for military purpose in directed-energy weapons or missile guidance systems. In a new study published in EPJ D, scientists from Bangladesh demonstrate that their proposed novel method, which is capable of producing such microwaves, offers a viable alternative to traditional approaches. The solution was developed by Md. Ghulam Saber and colleagues from the Islamic University of Technology in Gazipur, Bangladesh.

EPJ D – Graphical abstracts now required in EPJ D

Details: Published on 10 February 2015

We are pleased to inform the readers and authors of EPJ D that from now on articles published in the journal will feature a graphical abstract. While it is not meant to provide specific results, this element will serve the purpose of conveying visually the gist of the article, along with the title. Authors may use an item already present in the manuscript or a purpose-made graphic. The use of color is strongly encouraged. Images previously published under the copyright of other publishers cannot be considered.

EPJ A Highlight - Mechanisms of two-proton emission seen in three-body correlations

Details: Published on 10 February 2015

Sequential two-proton decay of the ¹⁶Ne E_r=7.57 MeV state. The fractional energy distribution (left) gives resonance energy in ¹⁵F while the angular distribution (right) determines I^π of the initial state.

Hitherto three-body correlations between decay products of nuclear resonances, unstable to the emission of two neutrons have been a very effective tool in the analysis of GSI-experiments on ⁵H, ¹⁰He, ¹³Li, and ¹⁴Be. Here the first report is given about the mechanisms for two-proton emission from states in ¹⁶Ne, representing the presently most complete study of this nucleus. One-neutron knockout from ¹⁷Ne populated the ¹⁶Ne(g.s.) (E_r=1.39 MeV, Γ=0.08 MeV) above the ¹⁴O+p+p threshold, and resonances at E_r=3.22 MeV and 7.57 MeV. The decay mechanisms were revealed analysing three-body energy correlations in the ¹⁴O+p+p system. It was found that the ¹⁶Ne(g.s.) undergoes a democratic three-body decay. In contrast to this, the ¹⁶Ne(21+) state emits protons through the ¹⁵F(g.s.) sequentially. The decay of 7.57 MeV state is well-described assuming emission of a proton from the d_5/2 shell to ¹⁵F(5/2⁺), which decays by d_5/2 proton emission to ¹⁴O(g.s.). By using R-matrix analysis and mirror symmetry this state was unambiguously identified as the third 2⁺ state in ¹⁶Ne.

J. Marganiec et al. (2014), Studies of continuum states in ¹⁶Ne using three-body correlation techniques, European Physical Journal A 51: 9, DOI 10.1140/epja/i2015-15009-0

EPJ Plus Highlight - Ultrafast laser for crafting ever thinner solar cells

Details: Published on 10 February 2015

Interaction between ultrashort pulse laser and a target.

Solar-cell efficiency depends on how thin it can be manufactured. Now, a new model exploits femtosecond laser sources to get higher efficiency at lower cost

The race for ever more efficient and cheaper solar cells tests the limits of manufacturing. To achieve this, photovoltaic solar cells need to become thinner and are made of more complex inner structures. Now, Italian scientists have investigated and expanded a model elucidating the dominant physical processes when ultra-fast lasers are used in manufacturing solar cells to these specifications. An article by Alberto Gurizzan and Paolo Villoresi from the University of Padova in Italy detailing this model has now been published in EPJ Plus.

EPJ ST Highlight - Analogue quantum computers: still wishful thinking?

Details: Published on 09 February 2015

Many challenges lie ahead before quantum annealing, the analogue version of quantum computation, contributes to solve combinatorial optimisation problems

Traditional computational tools are simply not powerful enough to solve some complex optimisation problems, like, for example, protein folding. Quantum annealing, a potentially successful implementation of analogue quantum computing, would bring about an ultra-performant computational method. A series of reviews in this topical issue of EPJ ST, guest-edited by Sei Suzuki from Saitama Medical University, Japan, and Arnab Das from the Indian Association for the Cultivation of Science, Kolkota, India, focuses on the state of the art and challenges in quantum annealing. This approach, if proven viable, could greatly boost the capabilities of large-scale simulations and revolutionise several research fields, from biology to economics, medicine and material science.

EPJ B Highlight - Probing qualities at the tips of nanocones

Details: Published on 01 February 2015

3D graphs of the local density of states with and without spin–orbital interaction for different distances r from the tip.

New understanding of electron behaviour at the tips of carbon nanocones could help provide candidates for use as a novel probe in atomic force microscopy

One of the ways of improving electrons manipulation is though better control over one of their inner characteristics, called spin. This approach is the object of an entire field of study, known as spintronics. Now, Richard Pincak from the Slovak Academy of Sciences and colleagues have just uncovered new possibilities for manipulating the electrons on the tips of graphitic nanocones. Indeed, in a study published in EPJ B, they have shown that because the tip area offers the greatest curvature, it gives rise, in the presence of defects, to an enhanced manifestation of a phenomenon called spin-orbit interaction. This, in turn, affects its electronic characteristics. These nanocones could thus become candidates for a new type of scanning probe in atomic force microscopy.

EPJ D Highlight - The power of light-matter coupling

Details: Published on 28 January 2015

Illustration of molecules coupled to the fundamental optical mode of a 145nm thick Fabry-Perot cavity. It features a typical example of the absorption spectrum of uncoupled (red line) and coupled (dark line) molecules. © A. Canaguier-Durand *et al.*

A theoretical study shows that strong ties between light and organic matter at the nanoscale open the door to modifying these coupled systems’ optical, electronic or chemical properties.

Light and matter can be so strongly linked that their characteristics become indistinguishable. These light-matter couplings are referred to as polaritons. Their energy oscillates continuously between both systems, giving rise to attractive new physical phenomena. Now, scientists in France have explained why such polaritons can remain for an unusual long time at the lowest energy levels, in such a way that alters the microscopic and macroscopic characteristics of their constituting matter. These findings thus pave the way for optical, electronic and chemical applications. The work has been published in EPJ D by Antoine Canaguier-Durand from the University of Strasbourg, France, and colleagues.

EPJ Data Science Highlight - Towards a scientific process freed from systemic bias

Details: Published on 25 January 2015

alt — Frank Schweitzer. © Frank Schweitzer

Large-scale analysis of bibliographic data can help us better understand the complex social processes in science and provide more accurate evaluation methods

Research on how science works—the science of science—can benefit from studying the digital traces generated during the research process, such as peer-reviewed publications. This type of research is crucial for the future of science and that of scientists, according to Frank Schweitzer, Chair of Systems Design at ETH Zurich, in Switzerland. Indeed, quantitative measures of scientific output and success in science already impact the evaluation of researchers and the funding of proposals. He shares his views in an Editorial spearheading a thematic series of articles entitled “Scientific networks and success in science”, published in EPJ Data Science. There, Schweitzer notes, “it is appropriate to ask whether such quantitative measures convey the right information and what insights might be missing.”

EPJ C Highlight - Shedding new light on dark matter

Details: Published on 13 January 2015

alt — Light yield versus energy of events passing all selection criteria. © G. Angloher and *et al.*

Study shows significant progress in determining what dark matter is not made of, thanks to much more sensitive detectors capable of identifying the presence of elusive particles, called WIMPs

According to astronomical observations, dark matter constitutes a five times greater proportion of the universe than ordinary matter, which only makes up 5% of the matter in the universe. The remaining 70% of the universe is known as dark energy. However, we still do not know what dark matter is made of. Indeed, none of the known elementary particles fulfil the criteria to explain dark matter. One theory suggests that it consists of as yet unknown elementary particles that interact only very weakly with ordinary matter, fittingly called WIMPs (Weakly Interacting Massive Particles). Now, members of the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) collaboration have analysed recent data showing what dark matter is not made of, from a new kind of detector for such particles. This work has recently been published in EPJ C.