The effects of maternal competence and situational stress level on children's help-seeking expectations across 4 to 6 years of age.

Help-seeking is a crucial problem-solving strategy for young children. However, it is not yet clear how children weigh different cues to make help-seeking decisions across preschool years, especially in caregiver-child interactions. The current study used a social expectation task to examine the effects of maternal competence and situational stress level on 4- to 6-year-old children's help-seeking expectations from a third-party perspective. Children's expectations of whether to seek help were measured. A total fo 135 Han Chinese children aged 4 to 6 years from an eastern city of China participated in this study. We found that 4- to 6-year-olds expected to seek more help from a competent mother than from an incompetent mother in low-stress conditions. When the stress level was high, however, they expected to seek help regardless of maternal competence levels. These results suggest that the interaction between the situational stress level and maternal competence determines young children's help-seeking expectations across preschool years. They further suggest that young children seek help from mothers in an active and discriminatory way.

Voltage-Controlled Dzyaloshinskii-Moriya Interaction Torque Switching of Perpendicular Magnetization.

Magnetization switching is the most important operation in spintronic devices. In modern nonvolatile magnetic random-access memory (MRAM), it is usually realized by spin-transfer torque (STT) or spin-orbit torque (SOT). However, both STT and SOT MRAM require current to drive magnetization switching, which will cause Joule heating. Here, we report an alternative mechanism, Dzyaloshinskii-Moriya interaction (DMI) torque, that can realize magnetization switching fully controlled by voltage pulses. We find that a consequential voltage-controlled reversal of DMI chirality in multiferroics can lead to continued expansion of a skyrmion thanks to the DMI torque. Enough DMI torque will eventually make the skyrmion burst into a quasiuniform ferromagnetic state with reversed magnetization, thus realizing the switching of a perpendicular magnet. The discovery is demonstrated in two-dimensional multiferroics, CuCrP_{2}Se_{6} and CrN, using first-principles calculations and micromagnetic simulations. As an example, we applied the DMI torque for simulating leaky-integrate-fire functionality of biological neurons. Our discovery of DMI torque switching of perpendicular magnetization provides tremendous potential toward magnetic-field-free and current-free spintronic devices, and neuromorphic computing as well.

Synthesis of 2,4,6-Trisubstituted Pyrimidines through Copper-Catalyzed [4 + 2] Annulation of α,ß-Unsaturated Ketoximes with Activated Nitriles.

The copper-catalyzed [4 + 2] annulation of α,ß-unsaturated ketoximes with activated nitriles for the rapid construction of 2,4,6-trisubstituted pyrimidines in moderate to good yields has been developed. The reaction features synthetic simplicity, good functional group tolerance, and gram-scale applicability. A plausible mechanism is proposed based on mechanistic investigations.

Acoustic spin rotation in heavy-metal-ferromagnet bilayers.

Through pumping a spin current from ferromagnet into heavy metal (HM) via magnetization precession, parts of the injected spins are in-plane rotated by the lattice vibration, namely acoustic spin rotation (ASR), which manifests itself as an inverse spin Hall voltage in HM with an additional 90° difference in angular dependency. When reversing the stacking order of bilayer with a counter-propagating spin current or using HMs with an opposite spin Hall angle, such ASR voltage shows the same sign, strongly suggesting that ASR changes the rotation direction due to interface spin-orbit interaction. With the drift-diffusion model of spin transport, we quantify the efficiency of ASR up to 30%. The finding of ASR endows the acoustic device with an ability to manipulate spin, and further reveals a new spin-orbit coupling between spin current and lattice vibration.

The effects of caregivers' responsiveness and situational stress levels on children's expectations of caregivers' support-giving behavior and willingness.

Children develop expectations of caregivers' support-giving during early-life interactions. The present study examined whether caregivers' responsiveness would influence young children's expectations of caregivers' support-giving behavior and willingness under different situational stress levels. We manipulated the caregivers' responsiveness and situational stress levels. Children were tested to determine their expectations of caregivers' support-giving behavior and willingness. Sixty-four (33 boys, Mage = 5.34) and 68 (34 boys, Mage = 5.25) Chinese Han children from a city in Southeast China participated in Studies 1 and 2, respectively. In Study 1, we created a separation condition (i.e., a moderate level of stress) and found that children's expectations of caregivers' support-giving behavior and willingness were significantly lower in the unresponsive condition than in the responsive condition. The expectations in the unresponsive condition decreased significantly compared with the initial expectations. In Study 2, we created a danger condition (i.e., a high level of stress) and found that caregivers' responsiveness had no significant effect on children's expectations of caregivers' support-giving behavior and willingness. These results imply that both caregivers' responsiveness and situational stress levels affect children's expectations of caregivers' support-giving. They further suggest that children aged 4-6 can simultaneously assess caregivers' responsiveness and situational stress levels while forming support-giving expectations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Reply to "Comment on 'Microscopic kinetic theory of the mean collision force of a particle moving in rarefied gases' ".

The relative speed distribution function [Eq. (2)] in the Comment is discussed. It shows that Eq. (2) in the Comment is not the distribution function that should be explored in our work and is therefore not applicable to our research.

Microscopic kinetic theory of the mean collision force of a particle moving in rarefied gases.

The friction of an incident particle interacting with the background molecules is a cornerstone in the nonequilibrium dynamics and statistics. It is reported that the Stokes force may fail while the Brown particle's size is small enough. In this work, the mean collision force of a small classical particle moving through the rarefied gases is analyzed by the direct calculation of the mean decrease of particle's velocity by elastic collisions. As an example, a whole velocity space applicable mean collision force in Maxwell gas is obtained. A self-consistent solution is further provided based on the numerical simulations. Within the low speed limit, comparison of the friction and the Stokes force has been demonstrated. Although the two forces are both proportional to the speed of the particle, their coefficients are different. Unlike the linear speed dependence of Stokes force, the linear behavior in rarefied gases is broken with increasing the speed of incident particle, and a quadratic speed dependence is resulted in high speed. This work clarifies the nonequilibrium dynamics of microscopic particles moving in rarefied gases, and can improve our microscopic understanding of the collision force.

Terahertz Faraday Rotation of SrFe12O19 Hexaferrites Enhanced by Nb Doping.

The magneto-optical and dielectric behavior of M-type hexaferrites as permanent magnets in the THz band is essential for potential applications like microwave absorbers and antennas, while are rarely reported in recent years. In this work, single-phase SrFe12-xNbxO19 hexaferrite ceramics were prepared by the conventional solid-state sintering method. Temperature dependence of dielectric parameters was investigated here to determine the relationship between dielectric response and magnetic phase transition. The saturated magnetization increases by nearly 12%, while the coercive field decreases by 30% in the x = 0.03 composition compared to that of the x = 0.00 sample. Besides, the Nb substitution improves the magneto-optical behavior in the THz band by comparing the Faraday rotation parameter from 0.75 (x = 0.00) to 1.30 (x = 0.03). The changes in the magnetic properties are explained by a composition-driven increase of the net magnetic moment and enhanced ferromagnetic exchange coupling. The substitution of the donor dopant Nb on the Fe site is a feasible way to obtain multifunctional M-type hexaferrites as preferred candidates for permanent magnets, sensors, and other electronic devices.

Copper-Catalyzed Three-Component Cascade Annulation for Divergent Syntheses of Imidazoles and Dihydroimidazoles.

The first example of divergent N-heterocycle syntheses through a copper-catalyzed three-component reaction of α,ß-unsaturated ketoximes, paraformaldehyde, and amines has been documented. In particular, this divergent synthetic strategy was achieved by controlling the reaction conditions to afford the corresponding imidazoles and dihydroimidazoles in moderate to good yields with a broad substrate scope and good functional group compatibility.

Supercurrent Induced by Chiral Coupling in Multiferroic/Superconductor Nanostructures.

We study the transport and the superconducting dynamics in a layer of type II superconductor (SC) with a normal top layer that hosts a helical magnetic ordering that gives rise to spin-current-driven ferroelectric polarization. Proximity effects akin to this heterostructure result in an anisotropic supercurrent transport and modify the dynamic properties of vortices in the SC. The vortices can be acted upon and controlled by electric gating or other means that couple to the spin ordering in the top layer, which, in turn, alter the superconducting/helical magnet coupling characteristics. We demonstrate, using the time dependent Ginzburg-Landau approach, how the spin helicity of the top layer can be utilized for pinning and guiding the vortices in the superconducting layer.

z = 3 antiferromagnetic quantum criticality driven by the Kondo effect.

We find that the Kondo effect results in a new universality class for an antiferromagnetic (AF) quantum critical point (QCP) in the heavy fermion quantum transition, described by deconfined bosonic spinons with the dynamical exponent z=3. We show that the thermodynamics and transport of the z=3 AF QCP are consistent with the well-known non-Fermi liquid physics such as the divergent Grüneisen ratio with an exponent 2/3 and temperature-linear resistivity. We propose that the hallmark of the Kondo-driven AF QCP is a uniform spin susceptibility that diverges with an exponent 2/3, remarkably consistent with the experimental observations for YbRh2Si2.

Twisted magnon beams carrying orbital angular momentum.

Low-energy eigenmode excitations of ferromagnets are spin waves or magnons that can be triggered and guided in magnonic circuits without Ohmic losses and hence are attractive for communicating and processing information. Here we present new types of spin waves that carry a definite and electrically controllable orbital angular momentum (OAM) constituting twisted magnon beams. We show how twisted beams emerge in magnonic waveguides and how to topologically quantify and steer them. A key finding is that the topological charge associated with OAM of a particular beam is tunable externally and protected against magnetic damping. Coupling to an applied electric field via the Aharanov-Casher effect allows for varying the topological charge. This renders possible OAM-based robust, low-energy consuming multiplex magnonic computing, analogously to using photonic OAM in optical communications, and high OAM-based entanglement studies, but here at shorter wavelengths, lower energy consumption, and ready integration in magnonic circuits.

lncSLdb: a resource for long non-coding RNA subcellular localization.

While long non-coding RNAs (lncRNAs) may play important roles in cellular function and biological process, we still know little about them. Growing evidences indicate that subcellular localization of lncRNAs may provide clues to their functionality. To facilitate researchers functionally characterize thousands of lncRNAs, we developed a database-driven application, lncSLdb, which stores and manages user-collected qualitative and quantitative subcellular localization information of lncRNAs from literature mining. The current release contains >11 000 transcripts from three species. Based on the accumulated region of lncRNAs, we classify transcripts into three basic localization types (nucleus, cytoplasm and nucleus/cytoplasm). In some conditions, the nucleus and cytoplasm types can be divided into three more accurate subtypes (chromosome, nucleoplasm and ribosome). Besides browsing and downloading data in lncSLdb, our system provides a set of comprehensive tools to search by gene symbols, genome coordinates or sequence similarity. We hope that lncSLdb will provide a convenient platform for researchers to investigate the functions and the molecular mechanisms of lncRNAs in the view of subcellular localization.

Room temperature magnetoelectric coupling in intrinsic multiferroic Aurivillius phase textured ceramics.

Spark plasma sintering was employed in order to obtain textured Aurivillius phase ceramics that simultaneously exhibit ferroelectric and ferromagnetic properties at room temperature. The sintered multiferroics are layer-structured, nearly single-phase materials. Although a small amount of the secondary phase consisting of magnetic Co and Fe was detected by SEM/EDX, a majority of the observed ferromagnetic behaviour was attributed to the Aurivillius phase Bi4.25La0.75Ti3Fe0.5Co0.5O15 based on the observed magnetic anisotropy. The ferroelectric switching was demonstrated to exist in the Aurivillius phase ceramics by measuring the current peaks upon electric field reversal. Piezoresponse force microscopy at room temperature revelaed substantial changes of the ferroelectric domain structure when the Aurivillius phase material is subjected to an external magnetic field.

Electric tuning of magnetization dynamics and electric field-induced negative magnetic permeability in nanoscale composite multiferroics.

Steering magnetism by electric fields upon interfacing ferromagnetic (FM) and ferroelectric (FE) materials to achieve an emergent multiferroic response bears a great potential for nano-scale devices with novel functionalities. FM/FE heterostructures allow, for instance, the electrical manipulation of magnetic anisotropy via interfacial magnetoelectric (ME) couplings. A charge-mediated ME effect is believed to be generally weak and active in only a few angstroms. Here we present an experimental evidence uncovering a new magnon-driven, strong ME effect acting on the nanometer range. For Co92Zr8 (20 nm) film deposited on ferroelectric PMN-PT we show via ferromagnetic resonance (FMR) that this type of linear ME allows for electrical control of simultaneously the magnetization precession and its damping, both of which are key elements for magnetic switching and spintronics. The experiments unravel further an electric-field-induced negative magnetic permeability effect.

Electric field mediated non-volatile tuning magnetism at the single-crystalline Fe/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 interface.

We report non-volatile electric-field control of magnetism modulation in Fe/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) heterostructure by fabricating an epitaxial Fe layer on a PMN-PT substrate using a molecular beam epitaxy technique. The remnant magnetization with a different electric field shows a non-symmetric loop-like shape, which demonstrates a change of interfacial chemistry and a large magnetoelectric coupling in Fe/PMN-PT at room temperature to realize low loss multistate memory under an electric field. Fitting with the angular-dependence of the in-plane magnetization reveals that the magnetoelectric effect is dominated by the direct electric-field effect rather than the strain effect at the interface. The magnetoelectric effect and the induced surface anisotropy are found to be dependent on the Fe film thickness and are linear with respect to the applied electric field.

Polarization and magnetization dynamics of a field-driven multiferroic structure.

We consider a multiferroic chain with a linear magnetoelectric coupling induced by electrostatic screening at the ferroelectric/ferromagnet interface. We study theoretically the dynamic ferroelectric and magnetic response to external magnetic and electric fields by utilizing an approach based on coupled Landau-Khalatnikov and finite-temperature Landau-Lifshitz-Gilbert equations. Additionally, we make comparisons with Monte Carlo calculations. It is demonstrated that for material parameters corresponding to BaTiO(3)/Fe the polarization and the magnetization are controllable by external magnetic and electric fields, respectively.