Highlights

Every year, a committee of experts sits down with a tough job to do: from among all ICREA publications, they must find a handful that stand out from all the others. This is indeed a challenge. The debates are sometimes heated and always difficult but, in the end, a shortlist of  the most outstanding publications of the year is produced. No prize is awarded, and the only additional acknowledge is the honour of being chosen and highlighted by ICREA. Each piece has something unique about it, whether it be a particularly elegant solution, the huge impact it has in the media or the sheer fascination it generates as a truly new idea. For whatever the reason, these are the best of the best and, as such, we are proud to share them here.

LIST OF SCIENTIFIC HIGHLIGHTS

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  • The role of sea birds as carriers of pollutants over long distances (2022)

    Brucet, Sandra (UVIC)

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    The role of sea birds as carriers of pollutants over long distances

    The Arctic is a fragile ecosystem extremely sensitive to environmental changes and that is currently exposed to multiple environmental stressors such as contamination. As a consequence, the Greenlandic population has unexpectedly relatively high levels of organohalogen compounds (i.e. organic chemicals), which directly affect child development, immune function and reproductive abilities.

    Long-range atmospheric transport is one of the main routes for organohalogen compounds to reach Greenland, but the role of biovectors cannot be ignored. For example, migratory species travel thousands of miles towards the Arctic, and thus can carry pollutants to the remote areas.

    Here we aimed to understand the role of sea birds as carriers of pollutants over long distances. For this reason we studied three lakes, one with a little auk (Alle alle) bird colony and two without these seabirds. The concentrations of all organohalogen compounds were substantially greater in the lake with the bird colony, indicating the strong influence of these seabirds in the transport and deposition of these compounds to remote sites. The organohalogen deposition was highest in the upper sediments of the polynya lake. Our results showed that, despite restrictions and regulations, bird transport continues to introduce considerable amounts of organohalogen pollutants to the Arctic regions.

  • The exceptional Late Roman shipwreck of Ses Fontanelles (Mallorca, Spain) (2022)

    Cau Ontiveros, Miguel Ángel (UB)

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    The exceptional Late Roman shipwreck of Ses Fontanelles (Mallorca, Spain)

    In the summer of 2019, after a strong storm, the Late Roman wreck of Ses Fontanelles appeared on one of the busiest beaches in Mallorca. The Consell de Mallorca promoted an agreement with the University of Barcelona, University of Cádiz, and University of the Balearic Islands to develop the project ARQUEOMALLORNAUTA (2021–2023) to study the shipwreck. The project is led by M.A. Cau, D. Bernal, J. Cardell and E. García.

    The excavations have allowed recovering the cargo of the boat in an excellent state of preservation. Around 300 transport amphorae have been recovered. These are containers used to transport fermented fish sauce, oil, and wines or fruits preserved in vine derivatives. Many of these amphorae present painted inscriptions (tituli picti) and the original paleocontents, which is a unique occasion at a global level. The presence of around a hundred painted inscriptions makes the wreck of Ses Fontanelles the most extensive collection of tituli picti in Spain, and one of the most important in the entire Roman world. Part of the cargo could have been shipped by ecclesiastical authorities, as deduced from the inscription that appeared on the ceramic stoppers that sealed some of the amphorae, with names and with the Chrismon (or monogram of Christ). In addition, it is worth highlighting the typology of these amphorae since it has been possible to identify some unknown containers.

    During the excavation, exceptional archaeological pieces appeared. This is the case of an arch drill used by riverside carpenters for the repair of the boat, the first of its kind in Spain and one of the few preserved around the World; two shoes (one of esparto and one of leather); ropes used in the boat and organic remains of diverse nature. We must also highlight the excellent state of preservation of the boat's hull, thanks to the anoxic burial environment.

    This is an exceptional shipwreck. It departed from Carthago Spartaria (Cartagena) or nearby and sunk in Mallorca in the initial phase of Late Antiquity (4th century AD). It is the first known Roman wreck with cargo from this region in Mediterranean waters.  

  • Controlling bound states of artificial atoms and photons (2022)

    Chang, Darrick (ICFO)

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    Controlling bound states of artificial atoms and photons

    Engineering the electromagnetic environment of a quantum optical emitter can give rise to a plethora of exotic light-matter interactions. As one prominent example, photonic lattices can seed long-lived atom-photon bound states, in which a photon becomes confined around the atom trying to emit it. Here, we experimentally explore this exotic atom-field interaction and access previously unexplored regimes, using a novel microwave architecture consisting of an array of compact superconducting resonators in which we have embedded two frequency-tunable artificial atoms. Among the key results, we demonstrate coherent interactions between two atom-photon bound states, in both resonant and dispersive regimes, that are suitable for the implementation of quantum computing gates. The presented architecture holds promise for quantum simulation with tunable-range interactions and photon transport experiments in the nonlinear regime.

  • Biological nitrogen fixation in food crops- A major step toward the Holy Grail of Agricultural Sustainability (2022)

    Christou, Paul (UdL)

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    Biological nitrogen fixation in food crops- A major step toward the Holy Grail of Agricultural Sustainability

    Crops require nitrogen for growth and productivity because it is a major component of DNA, proteins, chlorophyll and energy-storage molecules such as ATP. Most crops depend on supplies of nitrate and ammonium from industrial synthetic fertilizers, but more than half of these inputs remain unassimilated, spilling over or leaching into rivers and lakes as a major source of pollution. Leguminous crops such as peas and beans harbour bacteria that convert nitrogen gas directly into ammonia using an enzyme called nitrogenase. This process is known as biological nitrogen fixation. The introduction of nitrogenase genes into crop plants would provide the machinery needed to fix nitrogen independently. However, the process is extremely complex because many different individual proteins are required not only as the direct structural components of nitrogenase but also accessory proteins needed for its assembly and the provision of energy. The major protein components are also extremely oxygen sensitive. The researchers overcame this critical bottleneck by producing functional dinitrogenase reductase (Fe protein, NifH) and the nitrogenase cofactor maturase (NifB) in separate transgenic rice lines. This is a major bioengineering advance as it tears down two technical roadblocks and shows the path to make nitrogen-fixing cereals. The achievement removes one of the major constraints hindering biological nitrogen fixation in crops and sets the stage for the assembly of a complete and functional nitrogenase complex in plants. Further work to establish plants containing the full nitrogenase would have a lasting impact on global food security. One of the major impacts of the work in the long term will be in low- and middle-income countries, which cannot afford expensive nitrogen fertilizers. The work is part of a research program funded by a grant from the Bill & Melinda Gates Foundation.

  • MiOS, a tool to reveal how genes fold (2022)

    Cosma, Maria Pia (CRG)

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    MiOS, a tool to reveal how genes fold

    Our genome is like a long thread of wool that can be knitted or folded in 3D giving rise to different shapes. 3D folding is dynamic and tightly regulated by the cells. This is because, by making certain regions of the thread more compact or accessible, 3D gene folding regulates gene function. Yet, we lacked tools to understand how genes fold within the nucleus of our cells. 

    In this work, we developed a strategy to reveal how genes fold in 3D with unprecedented detail. We called it Modelling immuno-OligoSTORM or MiOS as it combines STORM super-resolution microscopy, sequencing-based data and modeling to generate 3D models of genes with nanometric resolution. Thus, MiOS can help researchers to virtually navigate inside genes, revealing how they are organised at a completely new scale and how this regulates function.

  • Self-Configuring Smart Surfaces for 6G Future Mobile Networks (2022)

    Costa Perez, Xavier (i2CAT)

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    Self-Configuring Smart Surfaces for 6G Future Mobile Networks

    Reconfigurable Intelligent Surfaces (RISs) are considered one of the key disruptive technologies towards future 6G networks.

    RISs are revolutionizing the traditional wireless communication paradigm by controlling the electromagnetic waves propagation properties of impinging signals at will. A major roadblock for RIS is though the need for a fast and complex control channel to continuously adapt to the ever-changing wireless channel conditions.

    In our work, we asked ourselves the question: Would it be feasible to remove the need for control channels for RISs? We analyzed the feasibility of devising Self-Configuring Smart Surfaces that can be easily and seamlessly installed throughout the environment without requiring any modifications to deployed mobile networks.

    To this aim we designed MARISA, a self-configuring metasurfaces absorption and reflection solution.

    Our results show that surprisingly, MARISA achieves outstanding performance, rivaling with state-of-the-art smart surfaces solutions comprising control channel-driven RISs solutions, but without the need of such control channel.

    If successful in the marketplace, self-configuring smart surfaces would significatly drop their deployment barrier for 6G networks with the potential of becoming the most energy saving to date to mobile networks densification.