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This study investigated the size–frequency distribution of 512 landslides triggered by heavy rain in July 2018 on Omishima Island, western Japan. Since the island has undergone rapid land use and land cover changes in recent decades, this study statistically examined the impact of past land cover changes on the shape of, and local variability in, the size–frequency distribution using the inverse gamma model. The possible influence of rainfall conditions was also examined. The landslides were classified based on the severity of anthropogenic disturbance and rainfall using a 56-year (1962–2018) land cover trajectory map and hourly rainfall distribution data. The results indicated that the land cover change (mainly forest conversion into farmland and its abandonment) affected the size and frequency of landslides that occurred decades after the disturbance. Although all landslide groups had similar small rollovers (location of probability peak; 0.042–0.075 × 10−3 km2), the scaling exponents of the negative power-law decay were lower for landslides in secondary forest and newly developed farmland (ρ = 1.084–1.231) than in old forest and farmland (ρ = 2.504–2.611). This difference is considered significant compared to general exponent values (ρ = 2.30 ± 0.56), suggesting that farmland development after 1962 caused widespread slope instability, leading to an increase in the proportion of large landslides. By contrast, no clear correlations with rainfall intensity were found, primarily due to complex localised variations in rainfall conditions.

In ferromagnetic metal (FM)/non-magnetic metal (NM) bilayer structures, dynamical spin injection is primarily attributed to spin pumping at the interface. However, thermal effects, such as the spin (dependent) Seebeck effect (S(d)SE) caused by FMR heating effect, are also expected to contribute, particularly farther from the interface within the FM layer. In this study, the detailed mechanism of dynamical spin injection in CoFeB/Pt bilayer films has been investigated. We demonstrate the proper evaluation of the CoFeB thickness dependence of inverse spin Hall voltage by subtracting the signal from single CoFeB system. The dynamical spin injection and FMR heating effect were observed to significantly depend on thickness. Additionally, we separated the contributions of SSE and SdSE by focusing on their diffusion properties and found that SSE is larger than SdSE in the CoFeB/Pt bilayer film.

Obesity is a growing global health concern and has been associated with increased mortality from various cancer types, including hematological malignancies. However, evidence for this association in Asian populations, particularly among Japanese adults, remains limited. Thus, this study aimed to examine the association between obesity and mortality due to hematological malignancies. Data from 97,073 participants in the Japan Collaborative Cohort (JACC) Study were analyzed. The participants were followed for a mean duration of 17 years. Body mass index (BMI) was calculated using self-reported height and weight and categorized as underweight (<18.5 kg/m²), normal-weight (18.5–24.9 kg/m²), overweight (25.0–29.9 kg/m²), and obesity (≥30.0 kg/m²). Mortality data for hematological malignancies were obtained from death certificates. Cause-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models, with adjustments made for demographic, lifestyle, and socioeconomic factors. During follow-up, 479 died from hematological malignancies, including lymphoma (n = 200), multiple myeloma (n = 107), and leukemia (n = 166; 106 myeloid leukemia). Compared with normal-weight individuals, those classified as obese exhibited a significantly higher risk of mortality from all hematological malignancies (HR: 1.78; 95% CI: 1.02–3.11), multiple myeloma (HR: 2.75; 95% CI: 1.09–6.94), leukemia (HR: 2.47; 95% CI: 1.07–5.69), and particularly myeloid leukemia (HR: 3.89; 95% CI: 1.66–9.11). No significant association was observed between BMI and lymphoma-related mortality. Obesity is significantly associated with increased mortality from multiple myeloma and leukemia, especially myeloid leukemia, in Japanese adults. These findings underscore the importance of obesity as a modifiable risk factor for certain hematological malignancies in this population.

A key element in spintronics is the spin-transfer effect, by which the magnetization in a nanomagnet can be switched. The effect has already been demonstrated using spin-polarized electrical currents, but now reversible magnetization switching has been achieved using a pure, chargeless spin current. A number of proposed next-generation electronic devices, including novel memory elements 1 and versatile transistor circuits 2 , rely on spin currents, that is, the flow of electron angular momentum. A spin current may interact with a magnetic nanostructure and give rise to spin-dependent transport phenomena, or excite magnetization dynamics 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 . In contrast to a spin-polarized charge current, a pure spin current does not produce any charge-related spurious effects 12 , 13 . One way to produce a pure spin current is non-local electrical-spin injection 12 , 13 , 14 , 15 , 16 , 17 , 18 , but this approach has suffered so far from low injection efficiency. Here, we demonstrate a significant enhancement of the non-local injection efficiency in a lateral spin valve prepared with an entirely in situ fabrication process. Improvements to the interface quality and the device structure lead to an increase of the spin-signal amplitude by an order of magnitude. The generated pure spin current enables the magnetization reversal of a nanomagnet with the same efficiency as in the case of using charge currents. These results are important for further theoretical developments in multi-terminal structures 2 , but also with a view towards realizing novel devices driven by pure spin currents.

Artificial multiferroic heterostructures, that is to say, ferromagnetic/ferroelectric heterostructures, have been the subject of considerable research interest as a potential material basis for the creation of novel energy-efficient device applications. Given that polarization reversal occurs in ferroelectric materials when an electric field is applied, it is possible to modulate the magnetic properties of a ferromagnetic layer due to changes in the polarization charge associated with a ferroelectric material, or due to exchange coupling, ionic transport, or orbital hybridization at the interface between the ferromagnetic and ferroelectric materials. Another essential characteristic of ferroelectric materials is their inverse piezoelectricity, which induces strain through the application of an electric field. The inverse piezoelectric strain is transferred to the ferromagnetic layer, thereby modulating the magnetic properties due to the magnetoelastic effect. In comparison to the various effects, the influence of strain transfer on magnetic properties is particularly pronounced, offering promising avenues for controlling magnetic properties via an electric field without the use of an electric current. This review article aims to present an overview of recent developments in the field of electric field effects on magnetic properties, with a particular focus on the role of strain transfer in magneto-electric effects. The potential applications of artificial multiferroic heterostructures are discussed, including the control of magnetic anisotropy, as well as the manipulation of perpendicular magnetic anisotropy, magnetoresistance, interlayer exchange coupling, spin wave propagation, spin damping, magnetic phase, and superconductivity. The article concludes with a consideration of the future prospects of artificial multiferroic heterostructures for next-generation device applications.

Due to COVID-19, many countries including Japan have implemented a suspension of economic activities for infection control. It has contributed to reduce the transmission of COVID-19 but caused severe economic losses. Today, several promising vaccines have been developed and are already being distributed in some countries. Therefore, we evaluated various vaccine and intensive countermeasure strategies with constraint of economic loss using SEIR model to obtain knowledge of how to balance economy with infection control in Japan. Our main results were that the vaccination strategy that prioritized younger generation was better in terms of deaths when a linear relationship between lockdown intensity and acceptable economic loss was assumed. On the other hand, when a non-linearity relationship was introduced, implying that the strong lockdown with small economic loss was possible, the old first strategies were best in the settings of small basic reproduction number. These results indicated a high potential of remote work when prioritizing vaccination for the old generation. When focusing on only the old first strategies as the Japanese government has decided to do, the strategy vaccinating the young next to the old was superior to the others when a non-linear relationship was assumed due to sufficient reduction of contact with small economic loss.

Background: Previous research has established that women accumulate less moderate-to-vigorous physical activity (MVPA) than men. To date, however, little is known about the gender differences in device-based activity patterns of sedentary behavior (SB) and light-intensity physical activity (LPA). We aimed to compare time spent in SB and different intensities of physical activity taking into account of co-dependence of time use domains.Methods: This cross-sectional study was conducted in Suttu town, Hokkaido, Japan. Data were analyzed from 634 Japanese adults (278 men, aged 19–92 years) who provided valid accelerometer (HJA-750C) data. Gender differences in activity behavior patterns were tested using multivariate analysis of covariance (MANCOVA) based on isometric log-ratio transformations of time use, adjusting for age. We also developed bootstrap percentile confidence intervals (CI) to support the interpretation of which behavior differed between genders.Results: Overall, participants had percent time spent in SB, LPA, MVPA during wearing time (mean, 14.8 hours) corresponding to 53.9%, 41.7%, and 4.4% of wearing time, respectively. Activity behavior patterns differed significantly between genders after controlling for time spent in all activities. Women spent relatively 13.3% (95% CI, 9.9–15.9%) less time in SB and 19.8% (95% CI, 14.9–24.6%) more time in LPA compared to men. The difference of time spent in MVPA was not statistically significant.Conclusions: In contrast with previous studies, our findings suggest that Japanese women are more physically active than men when all intensities of activities are considered. Given the health benefits of LPA, evaluating only MVPA may disproportionately underestimate the level of physical activity of women.

BackgroundPrevious studies, which examined the association between employment status and postpartum depression, were limited by binary or ternary employment status measures (employed/unemployed or full-time/part-time/unemployed). This study examined the association between detailed employment status during pregnancy and risk of depressive symptomatology 1 month after childbirth, and the effect modification by one’s perceived level of social support and household equivalent income.MethodsOur study examined 76 822 participants in the Japan Environment and Children’s Study. The exposure included maternal employment status during pregnancy (regular workers, dispatched workers, part-time workers, self-employed workers, non-employed and others), and the outcome was depressive symptomatology 1 month after childbirth: Edinburgh Postnatal Depression Scale (EPDS scores ≥9 and ≥13). Adjusted ORs and 95% CIs of depressive symptomatology associated with employment status were calculated by multivariable logistic regression. Subgroup analyses by perceived level of social support and household equivalent income were conducted.ResultsCompared with regular workers, the risk of depressive symptomatology (EPDS score ≥9) was higher for non-employed and others, and that (EPDS score ≥13) was so for part-time workers. There was no significant interaction by perceived level of social support and household equivalent income in the associations. However, part-time workers and non-employed had excess risk of depressive symptomatology among women with lower perceived level of social support, but not among those with the higher one.ConclusionCompared with regular workers, part-time workers and non-employed had an increased risk of depressive symptomatology, which was confined to women with lower perceived level of social support.

Strongly-interacting nanomagnetic arrays are ideal systems for exploring reconfigurable magnonics. They provide huge microstate spaces and integrated solutions for storage and neuromorphic computing alongside GHz functionality. These systems may be broadly assessed by their range of reliably accessible states and the strength of magnon coupling phenomena and nonlinearities. Increasingly, nanomagnetic systems are expanding into three-dimensional architectures. This has enhanced the range of available magnetic microstates and functional behaviours, but engineering control over 3D states and dynamics remains challenging. Here, we introduce a 3D magnonic metamaterial composed from multilayered artificial spin ice nanoarrays. Comprising two magnetic layers separated by a non-magnetic spacer, each nanoisland may assume four macrospin or vortex states per magnetic layer. This creates a system with a rich 16 N microstate space and intense static and dynamic dipolar magnetic coupling. The system exhibits a broad range of emergent phenomena driven by the strong inter-layer dipolar interaction, including ultrastrong magnon-magnon coupling with normalised coupling rates of Δ f ν = 0.57 , GHz mode shifts in zero applied field and chirality-control of magnetic vortex microstates with corresponding magnonic spectra. Extending magnetic nanostructures into three dimensions offers a vast increase in potential functionalities, but this typically comes at the expense of ease of fabrication and measurement. Here, Dion et al. demonstrate an approach to creating three dimensional magnetic nanostructures while retaining easy fabrication and readout of established two dimensional approaches.

Van der Waals (vdW) two-dimensional (2D) materials have unleashed unprecedented opportunities to probe emerging physics that could be potential candidates for various functional applications. In particular, vdW 2D magnetic materials exhibit significant potential for advanced spintronic devices. Recently, Fe3GaTe2 has been discovered to possess the room-temperature ferromagnetic property with an intrinsic perpendicular magnetic anisotropy (PMA). Furthermore, considerably large anomalous Hall and Nernst angles have been reported recently. These groundbreaking findings pave the way for significant advances in high density random-access memory as well as energy harvesting devices based on spin conversion. Enhancements in the PMA and Curie temperature contribute to improved performance with reliable operation in a wide temperature range above room temperature. Moreover, the exploration of giant anomalous Hall and Nernst angles is a crucial factor for the efficient operation of spintronic devices. In this study, we demonstrate that the application of pressure to the Fe3GaTe2 2D ferromagnetic film strengthens the interlayer coupling, resulting in an improved PMA property. In addition, the application of pressure has been found to significantly increase the anomalous Hall angle. Our findings suggest that the application of pressure effectively controls the vdW interlayer coupling, thereby manipulating the ferromagnetic and spin-conversion properties of the 2D materials.Van der Waals 2D magnetic materials are promising for spintronic devices due to their tunable large anomalous Hall and Nernst angles. Here, the magneto-transport properties of Fe3GaTe2 films are investigated under pressure, demonstrating a robust perpendicular magnetic anisotropy at room temperature and an enhancement of the anomalous Hall angle.