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Quantum sensing uses properties of quantum mechanics to go beyond what is possible with traditional measurement techniques. In particle physics, key problems in which quantum sensing can have a vital role include neutrino properties, tests of fundamental symmetries (Lorentz invariance and the equivalence principle, searches for electric dipole moments and possible variations of the fundamental constants), the search for dark matter and testing ideas about the nature of dark energy. Quantum sensor technologies using atom interferometry, optomechanical devices, or atomic and nuclear clocks are inherently relevant for low-energy physics, but other platforms, such as quantum dots, superconducting devices or spin sensors, might also be useful in future high-energy particle physics detectors. This Perspective explores the opportunities for these technologies in future particle physics experiments and outlines the challenges that could be tackled through collaborative efforts.Quantum sensing exploits properties of quantum systems to go beyond what is possible with traditional measurement techniques, hence opening exciting opportunities in both low-energy and high-energy particle physics experiments.

Hadron properties are modified when the hadron is embedded in a nuclear medium. Here we discuss the Gerasimov-Drell-Hearn, GDH, sum rule for polarised photoproduction from a polarised nucleon within a polarised nuclear target. Strong enhancement is expected with the suppression of the proton and nucleon resonance masses and enhancement of the proton’s anomalous magnetic moment in medium. This could be tested in polarised photoproduction experiments with interesting targets being polarised deuterons, 3 He, 6 Li and 7 Li. The largest contribution to the GDH sum rule comes from the Δ resonance excitation. In existing data with polarised deuterons and 3 He the Δ excitation is shifted to slightly lower energy when compared to model predictions where the Δ is treated with its free mass.

Key messageA simple and versatile ternary vector system that utilizes improved accessory plasmids for rapid maize transformation is described. This system facilitates high-throughput vector construction and plant transformation.The super binary plasmid pSB1 is a mainstay of maize transformation. However, the large size of the base vector makes it challenging to clone, the process of co-integration is cumbersome and inefficient, and some Agrobacterium strains are known to give rise to spontaneous mutants resistant to tetracycline. These limitations present substantial barriers to high throughput vector construction. Here we describe a smaller, simpler and versatile ternary vector system for maize transformation that utilizes improved accessory plasmids requiring no co-integration step. In addition, the newly described accessory plasmids have restored virulence genes found to be defective in pSB1, as well as added virulence genes. Testing of different configurations of the accessory plasmids in combination with T-DNA binary vector as ternary vectors nearly doubles both the raw transformation frequency and the number of transformation events of usable quality in difficult-to-transform maize inbreds. The newly described ternary vectors enabled the development of a rapid maize transformation method for elite inbreds. This vector system facilitated screening different origins of replication on the accessory plasmid and T-DNA vector, and four combinations were identified that have high (86–103%) raw transformation frequency in an elite maize inbred.

In positron emission tomography, as much as 40% of positron annihilation occurs through the production of positronium atoms inside the patient’s body. The decay of these positronium atoms is sensitive to metabolism and could provide information about disease progression. New research is needed to take full advantage of what positronium decays reveal.In positron emission tomography, up to 40% of positron annihilation occurs through the production of positronium atoms in the patient’s body, whose decay could provide information about disease progression. New research is needed to take full advantage of this information.

The Higgs boson, a fundamental scalar boson with mass 125 GeV, was discovered at the Large Hadron Collider (LHC) at CERN in 2012. So far, experiments at the LHC have focused on testing the Higgs boson’s couplings to other elementary particles, precision measurements of the Higgs boson’s properties and an initial investigation of the Higgs boson’s self-interaction and shape of the Higgs potential. The Higgs boson mass of 125 GeV is a remarkable value, meaning that the underlying state of the Universe, the vacuum, sits very close to the border between stable and metastable, which may hint at deeper physics beyond the standard model. The Higgs potential also influences ideas about the cosmological constant, the dark energy that drives the accelerating expansion of the Universe, the mysterious dark matter that comprises about 80% of the matter component in the Universe and a possible phase transition in the early Universe that might be responsible for baryogenesis. A detailed study of the Higgs boson is at the centre of the European Strategy for Particle Physics update. Here we review the current understanding of the Higgs boson and discuss the insights expected from present and future experiments.The Higgs boson is central to our understanding of the structure of matter in high-energy particle physics: the origin of mass, stability of the vacuum and key issues in cosmology. Here we review recent progress in experiment and theory and the prospects for future discoveries.

One of the main challenges in nuclear and particle physics in the last 20 years has been to understand how the proton's spin is built up from its quark and gluon constituents. Quark models generally predict that about 60% of the proton's spin should be carried by the spin of the quarks inside, whereas high energy scattering experiments have shown that the quark spin contribution is small — only about 30%. This result has been the underlying motivation for about 1000 theoretical papers and a global program of dedicated spin experiments at BNL, CERN, DESY and Jefferson Laboratory to map the individual quark and gluon angular momentum contributions to the proton's spin, which are now yielding exciting results. This book gives an overview of the present status of the field: what is new in the data and what can be expected in the next few years. The emphasis is on the main physical ideas and the interpretation of spin data. The interface between QCD spin physics and the famous axial U(1) problem of QCD (eta and etaprime meson physics) is also highlighted.

Here we determine the complete genomic sequence of the Gram negative, γ-Proteobacterium Vibrio cholerae El Tor N16961 to be 4,033,460 base pairs (bp). The genome consists of two circular chromosomes of 2,961,146 bp and 1,072,314 bp that together encode 3,885 open reading frames. The vast majority of recognizable genes for essential cell functions (such as DNA replication, transcription, translation and cell-wall biosynthesis) and pathogenicity (for example, toxins, surface antigens and adhesins) are located on the large chromosome. In contrast, the small chromosome contains a larger fraction (59%) of hypothetical genes compared with the large chromosome (42%), and also contains many more genes that appear to have origins other than the γ-Proteobacteria. The small chromosome also carries a gene capture system (the integron island) and host ‘addiction’ genes that are typically found on plasmids; thus, the small chromosome may have originally been a megaplasmid that was captured by an ancestral Vibrio species. The V. cholerae genomic sequence provides a starting point for understanding how a free-living, environmental organism emerged to become a significant human bacterial pathogen.

Nerve growth factor (NGF) is involved in a variety of processes involving signalling, such as cell differentiation and survival, growth cessation and apoptosis of neurons 1 . These events are mediated by NGF as a result of binding to its two cell-surface receptors, TrkA and p75 (ref. 2 ). TrkA is a receptor with tyrosine kinase activity that forms a high-affinity binding site for NGF 3 . Of the five domains comprising its extracellular portion, the immunoglobulin-like domain proximal to the membrane (TrkA-d5 domain) is necessary and sufficient for NGF binding 4 . Here we present the crystal structure of human NGF in complex with human TrkA-d5 at 2.2 Å resolution. The ligand–receptor interface consists of two patches of similar size. One patch involves the central β-sheet that forms the core of the homodimeric NGF molecule and the loops at the carboxy-terminal pole of TrkA-d5. The second patch comprises the amino-terminal residues of NGF, which adopt a helical conformation upon complex formation, packing against the ‘ABED’ sheet of TrkA-d5. The structure is consistent with results from mutagenesis experiments for all neurotrophins, and indicates that the first patch may constitute a conserved binding motif for all family members, whereas the second patch is specific for the interaction between NGF and TrkA.

Many particles, such as electrons, protons, and neutrons, behave like spinning tops. Unlike classical tops, however, the spin of these particles is an intrinsic quantum mechanical phenomenon. This spin is responsible for many fundamental properties of matter, including the proton's magnetic moment, the different phases of matter in low-temperature physics, the properties of neutron stars, and the stability of the known universe. In recent experiments, a number of research groups have been seeking to shed some light on the puzzling origin of spin and how this might resolve some large discrepancies between theory and experiment.

Type I IFNs are unusually pleiotropic cytokines that bind to a single heterodimeric receptor and have potent antiviral, antiproliferative, and immune modulatory activities. The diverse effects of the type I IFNs are of differential therapeutic importance; in cancer therapy, an enhanced antiproliferative effect may be beneficial, whereas in the therapy of viral infections (such as hepatitis B and hepatitis C), the antiproliferative effects lead to dose limiting bone marrow suppression. Studies have shown that various members of the natural IFN-α family and engineered variants, such as IFN-con1, vary in the ratios between various IFN-mediated cellular activities. We used DNA shuffling to explore and confirm the hypothesis that one could simultaneously increase the antiviral and Th1-inducing activity and decrease the antiproliferative activity. We report IFN-α hybrids wherein the ratio of antiviral:antiproliferative and Th1-inducing: antiproliferative potencies are markedly increased with respsect to IFN-con1 (75- and 80-fold, respectively). A four-residue motif that overlaps with the IFNAR1 binding site and is derived by cross breeding with a pseudogene contributes significantly to this phenotype. These IFN-αs have an activity profile that may result in an improved therapeutic index and, consequently, better clinical efficacy for the treatment of chronic viral diseases such as hepatitis B virus, human papilloma virus, HIV, or chronic hepatitis C.