The accurate representation of data is essential in science communication. However, colour maps that visually distort data through uneven colour gradients or are unreadable to those with ...colour-vision deficiency remain prevalent in science. These include, but are not limited to, rainbow-like and red-green colour maps. Here, we present a simple guide for the scientific use of colour. We show how scientifically derived colour maps report true data variations, reduce complexity, and are accessible for people with colour-vision deficiencies. We highlight ways for the scientific community to identify and prevent the misuse of colour in science, and call for a proactive step away from colour misuse among the community, publishers, and the press.
The technological appeal of multiferroics is the ability to control magnetism with electric field. For devices to be useful, such control must be achieved at room temperature. The only single-phase ...multiferroic material exhibiting unambiguous magnetoelectric coupling at room temperature is BiFeO3 (refs 4 and 5). Its weak ferromagnetism arises from the canting of the antiferromagnetically aligned spins by the Dzyaloshinskii-Moriya (DM) interaction. Prior theory considered the symmetry of the thermodynamic ground state and concluded that direct 180-degree switching of the DM vector by the ferroelectric polarization was forbidden. Instead, we examined the kinetics of the switching process, something not considered previously in theoretical work. Here we show a deterministic reversal of the DM vector and canted moment using an electric field at room temperature. First-principles calculations reveal that the switching kinetics favours a two-step switching process. In each step the DM vector and polarization are coupled and 180-degree deterministic switching of magnetization hence becomes possible, in agreement with experimental observation. We exploit this switching to demonstrate energy-efficient control of a spin-valve device at room temperature. The energy per unit area required is approximately an order of magnitude less than that needed for spin-transfer torque switching. Given that the DM interaction is fundamental to single-phase multiferroics and magnetoelectrics, our results suggest ways to engineer magnetoelectric switching and tailor technologically pertinent functionality for nanometre-scale, low-energy-consumption, non-volatile magnetoelectronics.
Entropy-stabilized materials are stabilized by the configurational entropy of the constituents, rather than the enthalpy of formation of the compound. A unique benefit to entropy-stabilized materials ...is the increased solubility of elements, which opens a broad compositional space, with subsequent local chemical and structural disorder resulting from different atomic sizes and preferred coordinations of the constituents. Known entropy-stabilized oxides contain magnetically interesting constituents, however, the magnetic properties of the multi-component oxide have yet to be investigated. Here we examine the role of disorder and composition on the exchange anisotropy of permalloy/(Mg
Co
Ni
Cu
Zn
)O heterostructures. Anisotropic magnetic exchange and the presence of a critical blocking temperature indicates that the magnetic order of the entropy-stabilized oxides considered here is antiferromagnetic. Changing the composition of the oxide tunes the disorder, exchange field and magnetic anisotropy. Here, we exploit this tunability to enhance the strength of the exchange field by a factor of 10x at low temperatures, when compared to a permalloy/CoO heterostructure. Significant deviations from the rule of mixtures are observed in the structural and magnetic parameters, indicating that the crystal is dominated by configurational entropy. Our results reveal that the unique characteristics of entropy-stabilized materials can be utilized and tailored to engineer magnetic functional phenomena in oxide thin films.
Objective Postpartum depression in mothers is associated with developmental problems in their children. Many women who are depressed following childbirth are also depressed during pregnancy. The aim ...of this study was to examine the associations between maternal depressive symptoms during pregnancy and child development at 18 months of age.
Design A prospective cohort study, Avon Longitudinal Study of Parents and Children.
Setting The former county of Avon, southwest England.
Population All pregnant women in the defined area with delivery dates between April 1991 and December 1992, 9244 women and their children.
Methods Data were collected antenatally, at 18 and 32 weeks of gestation and at 8 weeks and 8 months postnatally, through postal questionnaires, including a self‐report measure of depression (Edinburgh Postnatal Depression Scale EPDS). By the time their child was 18 months old, women completed five further questionnaires about their children’s health and development.
Main outcome measure Child development at 18 months using a modified Denver Developmental Screening Test (modified DDST).
Results Applying the standard 12/13 cutoff, 1565 (14%) women were depressed antenatally but not at either time‐points postnatally. Employing the modified DDST, 893 (9%) children were developmentally delayed at 18 months of age. Persistent depression (EPDS ≥ 10 at both time‐points) is associated with developmental delay (adjusted OR 1.34, 95% CI 1.11–1.62). Applying the 12/13 and 14/15 cutoffs gave similar results. After further adjustment for postnatal depression, the effect sizes were slightly attenuated.
Conclusions These findings highlight the importance of depression in pregnancy. Some effects on child development attributed to postpartum depression are caused in part by depressive symptoms during pregnancy.
The sequencing of individual DNA strands with nanopores is under investigation as a rapid, low-cost platform in which bases are identified in order as the DNA strand is transported through a pore ...under an electrical potential. Although the preparation of solid-state nanopores is improving, biological nanopores, such as α-hemolysin (αHL), are advantageous because they can be precisely manipulated by genetic modification. Here, we show that the transmembrane β-barrel of an engineered αHL pore contains 3 recognition sites that can be used to identify all 4 DNA bases in an immobilized single-stranded DNA molecule, whether they are located in an otherwise homopolymeric DNA strand or in a heteropolymeric strand. The additional steps required to enable nanopore DNA sequencing are outlined.
A reversal of magnetization requiring only the application of an electric field can lead to low-power spintronic devices by eliminating conventional magnetic switching methods. Here we show a ...nonvolatile, room temperature magnetization reversal determined by an electric field in a ferromagnet-multiferroic system. The effect is reversible and mediated by an interfacial magnetic coupling dictated by the multiferroic. Such electric-field control of a magnetoelectric device demonstrates an avenue for next-generation, low-energy consumption spintronics.
Mid-ocean ridges, transform faults, subduction and continental collisions form the conventional theory of plate tectonics to explain non-rigid behaviour at plate boundaries. However, the theory does ...not explain directly the processes involved in intraplate deformation and seismicity. Recently, damage structures in the lithosphere have been linked to the origin of plate tectonics. Despite seismological imaging suggesting that inherited mantle lithosphere heterogeneities are ubiquitous, their plate tectonic role is rarely considered. Here we show that deep lithospheric anomalies can dominate shallow geological features in activating tectonics in plate interiors. In numerical experiments, we found that structures frozen into the mantle lithosphere through plate tectonic processes can behave as quasi-plate boundaries reactivated under far-field compressional forcing. Intraplate locations where proto-lithospheric plates have been scarred by earlier suturing could be regions where latent plate boundaries remain, and where plate tectonics processes are expressed as a 'perennial' phenomenon.
We report the measurement of thermal conductance of silicon nanowires at low temperature. It is demonstrated that the roughness at the nanometer scale plays a crucial role for the phonon transport in ...low-dimensional samples. To this end, using e-beam lithography, nanowires of size 200 nm by 100 nm and 10 μm long have been nanofabricated. Their thermal properties have been measured using the 3 ω method between 0.3 and 6 K. The change in the temperature behavior of the thermal conductance (quadratic temperature dependence of K(T)) is a signature of an intermediate regime lying between the classical Casimir regime and the quantum regime. The Casimir-Ziman model is used to show that this specific behavior originates in mesoscopic samples where the dominant phonon wavelength becomes commensurate to the characteristic length of the roughness of the nanowire surfaces.
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