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Superconductivity is ubiquitous as evidenced by the observation in many crystals including carrier-doped oxides and diamond. Amorphous solids are no exception. However, it remains to be discovered in quasicrystals, in which atoms are ordered over long distances but not in a periodically repeating arrangement. Here we report electrical resistivity, magnetization, and specific-heat measurements of Al–Zn–Mg quasicrystal, presenting convincing evidence for the emergence of bulk superconductivity at a very low transition temperature of T c ≅ 0.05 K. We also find superconductivity in its approximant crystals, structures that are periodic, but that are very similar to quasicrystals. These observations demonstrate that the effective interaction between electrons remains attractive under variation of the atomic arrangement from periodic to quasiperiodic one. The discovery of the superconducting quasicrystal, in which the fractal geometry interplays with superconductivity, opens the door to a new type of superconductivity, fractal superconductivity. Superconductivity is evidenced in crystals and amorphous solids, but remains to be discovered in quasicrystals. Here, Kamiya et al. report the emergence of bulk superconductivity in Al-Zn-Mg quasicrystal at a very low transition temperature about 0.05 K.

An experiment is performed using high-speed photography to elucidate the behaviours of jets formed by the interactions of two laser-induced tandem bubbles produced axisymmetrically for a range of dimensionless interaction parameters such as the bubble size ratio, $\\unicode[STIX]{x1D709}$ , the distance between the two cavitation bubbles, $l_{0}^{\\ast }$ , and the time difference in bubble generation, $\\unicode[STIX]{x0394}\\unicode[STIX]{x1D703}^{\\ast }$ . A strong interaction occurs for $l_{0}^{\\ast }<1$ . The first bubble produced (bubble A) deforms because of the rapid growth of the second bubble (bubble B) to create a pulsed conical jet, sometimes with spray formation at the tip, formed by the small amount of water confined between the two bubbles. This phenomenon is followed by bubble penetration, toroidal bubble collapse, and the subsequent fast contraction of bubble B accompanied by a fine jet. The formation mechanism of the conical jet is similar to that of a water spike developed in air from a deformed free surface of a single growing bubble; however, the pressures of the gases surrounding each type of jet differ. The jet behaviours can be controlled by manipulating the interaction parameters; the jet velocity is significantly affected by $\\unicode[STIX]{x1D709}$ and $l_{0}^{\\ast }$ , but less so by $\\unicode[STIX]{x0394}\\unicode[STIX]{x1D703}^{\\ast }$ for $\\unicode[STIX]{x0394}\\unicode[STIX]{x1D703}^{\\ast }>\\unicode[STIX]{x0394}\\unicode[STIX]{x1D703}_{c}^{\\ast }$ ( $\\unicode[STIX]{x0394}\\unicode[STIX]{x1D703}_{c}^{\\ast }$ being the critical birth-time difference). The optimum time of jet impact, at which bubble A reaches its maximum volume, depends on $\\unicode[STIX]{x0394}\\unicode[STIX]{x1D703}^{\\ast }$ . It is generally later for larger values of $\\unicode[STIX]{x1D709}$ . A pulsed jet could be used to create small pores in a cell membrane; therefore, the reported method may be useful for application in tandem-bubble sonoporation.

Lawrencium, with atomic number 103, has an isotope with a half-life of 27 seconds; even so, its first ionization potential has now been measured on an atom-at-a-time scale and agrees well with state-of-the-art theoretical calculations that include relativistic effects. The chemistry of element 103 The most dramatic modern revision of Mendeleev's periodic table of elements came in 1944 when Glenn T. Seaborg placed a new series of elements, the actinides (atomic numbers 89–103), below the lanthanides. In this issue of Nature , Yuichiro Nagame and colleagues report the first measurement of one of the basic atomic properties of element 103 (lawrencium), namely its first ionization potential. Lawrencium is only accessible via atom-at-a-time synthesis in heavy-ion accelerators, so experimental investigations of its properties are rare. Nagame and colleagues were able to reduce the number of atoms required to measure the ionization potential from billions to thousands, and these results — in agreement with the latest theoretical calculations — show that the last valence electron in lawrencium is the most weakly bound one in all actinides and any other element beyond group 1 of the periodic table. This signature — in a region of the periodic table where the sheer size of the atoms means that relativistic effects play a crucial role — confirms the end of the actinide series at element 103. The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row—including the actinides—even affecting ground-state configurations 1 , 2 . Atomic s and p 1/2 orbitals are stabilized by relativistic effects, whereas p 3/2 , d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP 1 ) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP 1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time 3 , 4 , 5 . Here we report that the experimentally obtained IP 1 of the heaviest actinide, lawrencium (Lr, atomic number 103), is electronvolts. The IP 1 of Lr was measured with 256 Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP 1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP 1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.

The impact of mid‐latitude oceanic frontal zones with sharp meridional sea‐surface temperature (SST) gradients on the middle atmosphere circulation during austral winter is investigated by comparing two idealized experiments with a high‐top gravity wave (GW) permitting general circulation model. Control run is performed with realistic frontal SST gradients, which are artificially smoothed in no‐front run. The control run simulates active baroclinic waves and GW generation around the mid‐latitude SST front, with GWs propagating into the stratosphere and mesosphere. In the no‐front run, by contrast, baroclinic‐wave activity is significantly suppressed, and GWs with smaller amplitude are excited and then dissipated at higher altitudes in the mesosphere. Westward wave forcing in the winter hemisphere was more pronounced in the control run up to ∼0.03 hPa, resulting in a more realistic reproduction of the middle atmospheric polar vortex. The results demonstrate the importance of realistic mid‐latitude ocean conditions for simulating the middle atmosphere circulation. Plain Language Summary The impact of the mid‐latitude oceanic fronts characterized by sharp sea‐surface temperature (SST) gradients is investigated using a global gravity‐wave permitting atmospheric model that represents the troposphere, stratosphere and mesosphere. Two idealized experiments were conducted with different SST profiles. Control run features a realistic SST profile characterized by frontal SST gradients in mid‐latitudes, while they are smoothed out artificially in the “no‐front” run. In winter the no‐front run simulates significantly suppressed generation of synoptic‐scale cyclones and anticyclones, which results in reduced upward propagation of higher‐frequency gravity waves into the stratosphere, exerting marked impact on the large‐scale circulation extending as high as the mesopause. Notably higher gravity wave activity in the control run leads to a weaker, and more realistic wintertime polar vortex in the stratosphere and mesosphere. This study emphasizes the potential influence of mid‐latitude oceanic conditions on the atmospheric circulation, not only in the troposphere but also throughout the stratosphere and mesosphere. Key Points High‐top global model simulations are conducted to examine the impact of a mid‐latitude oceanic front on the atmospheric circulation The oceanic front enhances tropospheric baroclinic‐wave activity and generation of gravity waves propagating into the middle atmosphere The enhanced gravity waves act to reduce cold bias of the wintertime polar vortex in the Southern Hemisphere middle atmosphere

During the past few decades, there has been a nationwide push to improve performance and persistence outcomes for STEM undergraduates. As part of this effort, recent research has emphasized the need for focus on not only improving the delivery of course content, but also addressing the social-psychological needs of students. One promising intervention type that has been proposed as a multifaceted way to address both cognitive and social-psychological aspects of the learning process is the learning community. Learning communities provide students with opportunities to build a strong support system in college and are generally associated with increased student engagement and integration with campus systems and cultures. In this study, we examine the impact of a learning community intervention for first-year biological sciences majors, the Enhanced Academic Success Experience (EASE) program. Incoming freshmen are assigned to EASE based on their SAT (or ACT equivalent) Math score, a metric demonstrated to be a key predictor of student success in the program. We find that enrollment in EASE is correlated with higher STEM course grades; an increase of 0.25 (on a 0-4 point scale) in cumulative first-year GPA; and gains in non-academic outcomes, such as measures of sense of belonging and academic integration. Further, these outcomes are more pronounced for particular subgroup populations. For example, whereas surveyed male students seemed to benefit academically from participating in a learning community, female students reported a greater sense of belonging in regard to the biological sciences major and reported higher values for behavioral indicators of academic integration. Lastly, we find that the EASE program is positively correlated with students' intention to stay in the biological sciences major. And, among the three race-oriented groups, this impact is most pronounced for under-represented students. In light of these findings, we discuss the potential of discipline-specific learning community programs to improve academic outcomes for students most at risk of leaving STEM majors, such as students underprepared for college level coursework.

By describing where animals go, biologging technologies (i.e. animal attached logging of biological variables with small electronic devices) have been used to document the remarkable athletic feats of wild animals since the 1940s. The rapid development and miniaturization of physiologging (i.e. logging of physiological variables such as heart rate, blood oxygen content, lactate, breathing frequency and tidal volume on devices attached to animals) technologies in recent times (e.g. devices that weigh less than 2 g mass that can measure electrical biopotentials for days to weeks) has provided astonishing insights into the physiology of free-living animals to document how and why wild animals undertake these extreme feats. Now, physiologging, which was traditionally hindered by technological limitations, device size, ethics and logistics, is poised to benefit enormously from the on-going developments in biomedical and sports wearables technologies. Such technologies are already improving animal welfare and yield in agriculture and aquaculture, but may also reveal future pathways for therapeutic interventions in human health by shedding light on the physiological mechanisms with which free-living animals undertake some of the most extreme and impressive performances on earth. This article is part of the theme issue 'Measuring physiology in free-living animals (Part I)'.

Cortical computation is distributed across multiple areas of the cortex by networks of reciprocal connectivity. However, how such connectivity contributes to the communication between the connected areas is not clear. In this study, we examine the communication between sensory and motor cortices. We develop an eye movement task in mice and combine it with optogenetic suppression and two-photon calcium imaging techniques. We identify a small region in the secondary motor cortex (MO s ) that controls eye movements and reciprocally connects with a rostrolateral part of the higher visual areas (V RL/A/AL ). These two regions encode both motor signals and visual information; however, the information flow between the regions depends on the direction of the connectivity: motor information is conveyed preferentially from the MO s to the V RL/A/AL , and sensory information is transferred primarily in the opposite direction. We propose that reciprocal connectivity streamlines information flow, enhancing the computational capacity of a distributed network. Reciprocal connectivity enables tightly coupled information processing across cortical areas. Here the authors develop a visual oculomotor task in mice, identify a small motor area required for it, and demonstrate selective exchange of sensory and motor information between the motor and sensory areas.

The mechanisms underlying the influence of the surface chemistry of inorganic materials on polymer structures and fracture behaviours near adhesive interfaces are not fully understood. This study demonstrates the first clear and direct evidence that molecular surface segregation and cross-linking of epoxy resin are driven by intermolecular forces at the inorganic surfaces alone, which can be linked directly to adhesive failure mechanisms. We prepare adhesive interfaces between epoxy resin and silicon substrates with varying surface chemistries (OH and H terminations) with a smoothness below 1 nm, which have different adhesive strengths by ~13 %. The epoxy resins within sub-nanometre distance from the surfaces with different chemistries exhibit distinct amine-to-epoxy ratios, cross-linked network structures, and adhesion energies. The OH- and H-terminated interfaces exhibit cohesive failure and interfacial delamination, respectively. The substrate surface chemistry impacts the cross-linked structures of the epoxy resins within several nanometres of the interfaces and the adsorption structures of molecules at the interfaces, which result in different fracture behaviours and adhesive strengths. The mechanisms of adhesion between polymers and inorganic materials are not fully understood. Here, authors demonstrate the clear evidence that the surface chemistry impacts the crosslinked structures of resins near the interfaces, resulting in different fracture behaviours and adhesive strengths.

The dynamic interaction between the traveling charges and the molecular vibrations is critical for the charge transport in organic semiconductors. However, a direct evidence of the expected impact of the charge-phonon coupling on the band dispersion of organic semiconductors is yet to be provided. Here, we report on the electronic properties of rubrene single crystal as investigated by angle resolved ultraviolet photoelectron spectroscopy. A gap opening and kink-like features in the rubrene electronic band dispersion are observed. In particular, the latter results in a large enhancement of the hole effective mass (> 1.4), well above the limit of the theoretical estimations. The results are consistent with the expected modifications of the band structures in organic semiconductors as introduced by hole-phonon coupling effects and represent an important experimental step toward the understanding of the charge localization phenomena in organic materials. The charge transport properties in organic semiconductors are affected by the impact of molecular vibrations, yet it has been challenging to quantify them to date. Here, Bussolotti et al. provide direct experimental evidence on the band dispersion modified by molecular vibrations in a rubrene single crystal.

The chemical characterization of the heaviest elements at the farthest reach of the periodic table (PT) and the classification of these elements in the PT are undoubtedly crucial and challenging subjects in chemical and physical sciences. The elucidation of the influence of relativistic effects on their outermost electronic configuration is also a critical and fascinating aspect. However, the heaviest elements with atomic numbers Z ≳ 100 must be produced at accelerators using nuclear reactions of heavy ions and target materials. Therefore, production rates for these elements are low, and their half-lives are as short as a few seconds to a few minutes; they are usually available in a quantity of only a few atoms at a time. Here, we review some highlighted studies on heavy actinide and light transactinide chemical characterization performed at the Japan Atomic Energy Agency tandem accelerator facility. We discuss briefly the prospects for future studies of the heaviest elements.