The preliminary impulse of the sudden commencement is simply explained by the generation of the compressional wave due to sudden compression of the dayside magnetopause and mode conversion from the ...compressional wave to the Alfvén wave in the magnetosphere. However, this simple model cannot explain a time delay of the peak displacement and longer duration time in the higher latitudes in the pre-noon and post-noon sectors of the polar region. Based on the global magnetohydrodynamic simulation of the magnetosphere–ionosphere system reveals that this peculiar behavior of the geomagnetic variation of the preliminary impulse is associated with temporal deformation of the ionospheric field-aligned current distribution of the preliminary impulse into a crescent shape; its lower-latitude edge extends toward the anti-sunward direction, and its higher-latitude edge almost stays on the same longitude near noon. Numerical simulations revealed that the deformation of the field-aligned current distribution is derived from different behaviors of the two current systems of the preliminary impulse. The first current system consists of the field-aligned current connected to the field-aligned current of the preliminary impulse in the lower latitude side of the ionosphere, the cross-magnetopause current, and the magnetosheath current (type L current system). The cross-magnetopause current is the inertia current generated in the acceleration front of the solar wind due to the sudden compression of the magnetosheath. Thus, the longitudinal speed of the type L current system in the ionosphere is the solar wind speed in the magnetosheath projected into the ionosphere. In contrast, the current system of the preliminary impulse connected to the field-aligned current of the preliminary impulse at higher latitude (type H current system) consists of the upward/downward field-aligned current in the pre-noon/post-noon sector, respectively, and dawn-to-dusk field-perpendicular current along the dayside magnetopause. The dawn-to-dusk field-perpendicular current moves to the higher latitudes in the outer magnetosphere over time. The field-aligned current of the type H current system is converted from the field-perpendicular current due to convergence of the return field-perpendicular current heading toward the sunward direction in the outer magnetosphere; the return field-perpendicular current is the inertia current driven by the magnetospheric plasma flow associated with compression of the magnetopause behind the front region of the accelerated solar wind. The acceleration front spreads concentrically from the subsolar point. Consequently, as the return field-perpendicular current is converted to the field-aligned current of the type H current system, it does not move much in the longitudinal direction over time because the dawn-to-dusk field-perpendicular current of the type H current system moves to the higher latitudes. Therefore, the high-latitude edge of the current distribution of the preliminary impulse in the ionosphere moves only slightly. Finally, we clarified that the conversion between field-perpendicular current and field-aligned current of the type L current system mainly occurs in the region where the Alfvén speed starts to increase toward the Earth. A region with a steep gradient of the Alfvén speed like the plasmapause is not always necessary for conversion from the field-perpendicular current to the field-aligned current. We also suggest the possible field-aligned structure of the standing Alfvén wave that may occur in the preliminary impulse phase.
Graphical Abstract
S486P substitution, emerged and is rapidly spreading in the USA (appendix pp 6–7), and is the latest variant of concern.7 Although the features of XBB.1.5 were reported by Yue and colleagues,8 a ...comprehensive understanding of the virological characteristics of newly emerging variants is needed for sustained global health. ...neutralisation assay revealed that XBB.1.5 was robustly resistant to BA.2 breakthrough infection sera (41-fold versus B.1·1, 20-fold versus BA.2) and BA.5 breakthrough infection sera (32-fold versus B.1·1, 9·5-fold versus BA.5; appendix pp 6–7). Supported in part by AMED SCARDA Japan Initiative for World-leading Vaccine Research and Development Centers UTOPIA (JP223fa627001, to KS), AMED SCARDA Program on R&D of new generation vaccine including new modality application (JP223fa727002, to Kei Sato); AMED Research Program on Emerging and Re-emerging Infectious Diseases (JP22fk0108146, to Kei Sato; JP21fk0108494 to G2P-Japan Consortium and Kei Sato; JP21fk0108425, to Kei Sato; JP21fk0108432, to Kei Sato); AMED Research Program on HIV/AIDS (JP22fk0410039, to Kei Sato); JST PRESTO (JPMJPR22R1, to Jumpei Ito); JST CREST (JPMJCR20H4, to Kei Sato); JSPS KAKENHI Grant-in-Aid for Early-Career Scientists (20K15767, Jumpei Ito); JSPS Core-to-Core Program (A. Advanced Research Networks) (JPJSCCA20190008, Kei Sato); JSPS Research Fellow DC2 (22J11578, to Keiya Uriu); The Tokyo Biochemical Research Foundation (to Kei Sato); and the project of National Institute of Virology and Bacteriology, Programme EXCELES, funded by the European Union, Next Generation EU (LX22NPO5103, to Jiri Zahradnik).
This article uses CPS gross flow data to analyze the business cycle dynamics of separation and job finding rates and quantify their contributions to overall unemployment variability. Cyclical changes ...in the separation rate are negatively correlated with changes in productivity and move contemporaneously with them, whereas the job finding rate is positively correlated with and tends to lag productivity. Contemporaneous fluctuations in the separation rate explain between 40 and 50% of fluctuations in unemployment, depending on how the data are detrended. This figure becomes larger when dynamic interactions between the separation and job finding rates are considered.
This paper explores a causal link between aging of the labor force and the declining trend in the real interest rate in Japan. We develop a search and matching model that features heterogeneous ...workers with respect to their ages and firm-specific skills. Using the model, we examine the long-run implications of the sharp drop in labor force entry in the 1970s. We show that the changes in the demographic structure induce significant low-frequency movements in per capita consumption growth and thus the real interest rate. The model suggests that aging of the labor force caused the real interest rate to decline by 1 percentage point between 1980 and 2010 in Japan.
•The paper explore a link between aging and the declining real interest rate in Japan.•Our model shows that aging can induce large movements in the real interest rate..•It resulted in the real rate to fall by 1 percentage point between 1980 and 2010.
After the global spread of the SARS-CoV-2 Omicron BA.2, some BA.2 subvariants, including BA.2.9.1, BA.2.11, BA.2.12.1, BA.4, and BA.5, emerged in multiple countries. Our statistical analysis showed ...that the effective reproduction numbers of these BA.2 subvariants are greater than that of the original BA.2. Neutralization experiments revealed that the immunity induced by BA.1/2 infections is less effective against BA.4/5. Cell culture experiments showed that BA.2.12.1 and BA.4/5 replicate more efficiently in human alveolar epithelial cells than BA.2, and particularly, BA.4/5 is more fusogenic than BA.2. We further provided the structure of the BA.4/5 spike receptor-binding domain that binds to human ACE2 and considered how the substitutions in the BA.4/5 spike play roles in ACE2 binding and immune evasion. Moreover, experiments using hamsters suggested that BA.4/5 is more pathogenic than BA.2. Our multiscale investigations suggest that the risk of BA.2 subvariants, particularly BA.4/5, to global health is greater than that of original BA.2.
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•BA.4/5 is resistant to immunity induced by BA.1 and BA.2 infections•Substitutions in the BA.4/5 spike contribute to immune escape and ACE2 binding strength•BA.4/5 is more fusogenic and more efficiently spread in human lung cells than BA.2•BA.4/5 spike-bearing virus is more pathogenic than BA.2 spike-bearing virus
The SARS-CoV-2 Omicron variants BA.4 and BA.5 are currently causing infections and COVID-19 morbidities worldwide. Compared with the earlier variant BA.2, BA.4/5 shows more efficient replication and is more fusogenic. Structural views as well as in vivo studies in hamsters explain the antibody evasion and increased pathogenicity of BA.4/5 over BA.2.
Physics-based simulations are important for elucidating the fundamental mechanisms behind the time-varying complex ionospheric conditions, such as ionospheric potential, against unprecedented solar ...wind variations incident on the Earth’s magnetosphere. However, carrying out an extensive parameter survey for comprehending the nonlinear solar wind density dependence of the ionospheric potential, for example, requires state-of-the-art global magnetohydrodynamic (MHD) simulations, which cannot be executed efficiently even on large-scale cluster computers. Here, we report the performance of a machine-learning based surrogate model for estimating the ionospheric potential outputs of a global MHD simulation, using the reservoir computing technique called echo state network (ESN). The trained ESN-based emulator demonstrates exceptional speed in conducting the parameter survey, which can lead to the identification of a solar wind density dependence of the ionospheric polar cap potential. Finally, we discuss future directions including the promising application for space weather forecasting.
Graphical Abstract
•1D7 is a monoclonal antibody that neutralizes the broad feline calicivirus strains.•Three repeated neutralizations allow the generation of the 1D7-resistant variants.•The amino acid substitutions in ...the P1 domain are associated with 1D7 neutralization escape.•Amino acid residues at the substitution sites of 1D7-resistant variants are highly conserved in FCV strains.
Feline calicivirus (FCV) causes upper respiratory tract diseases in cats and has highly variable antigenicity for neutralization of each strain. Neutralizing epitopes of FCV are currently found in the hypervariable region (HVR) in the P2 domain of the major capsid protein VP1. Due to its unique ability to neutralize various FCV strains, 1D7 is a monoclonal antibody that may recognize a novel neutralizing epitope. While other neutralizing epitopes were characterized by producing neutralization-resistant variants, only 1D7-resistant variants could not be obtained, and its epitope has not been identified in the previous studies. In this study, we successfully generated these variants by multiple passaging of the FCV F4 strain in the presence of 1D7 and discovered that several amino acid substitutions (K638N, R662G, and T666I in the P1 domain of VP1) are involved in the decreased binding of 1D7. These substitution sites are also highly conserved among FCV strains compared with the substitution sites of other neutralization-resistant variants found in the HVR. Our results indicate that amino acid substitutions in the P1 domain, which are not responsible for direct interaction with the FCV receptor, are associated with neutralization escape. Since FCV can be conveniently cultured in vitro and the receptor required for infection is known, a detailed analysis of the 1D7 epitope could shed more light on the neutralization mechanism of the epitopes of viruses belonging to the Caliciviridae.
Based upon recent global magnetohydrodynamic (MHD) simulations, we provide a theoretical foundation for magnetospheric dynamos driving large‐scale field‐aligned current (FAC) systems. In the ...framework of MHD, the dynamo is a process in which plasma thermal energy is converted to electromagnetic energy. Theoretical analysis using ideal MHD equations indicates the existence of two types of dynamos that allow this energy conversion. One is the expanding slow dynamo associated with flux tube expansion, and the other is the contracting slow dynamo associated with flux tube contraction. The expanding slow is a stationary dynamo without significant magnetic field curvature, with the field intensity gradient playing a central role. In contrast, the contracting slow is a dynamo with finite time variation and finite magnetic field curvature. A supplementary MHD simulation in this study, together with those in the past studies, indicates the existence of a general relation between the main voltage generator (i.e., dynamo) and the main FAC generator (i.e., divergence of FACs) that appears commonly for large‐scale FAC systems.. That is, the dynamo overlaps the FAC generator in a specific spatial configuration and that at the transition between compressible high beta plasma and incompressible low beta plasma. This overlap represents a coupling of slow mode and Alfvén mode disturbances. We performed linear analysis of that special configuration using ideal MHD equations and derived the general expression relating the voltage generator and the FAC generator.
Key Points
The magnetospheric dynamo driving large‐scale field‐aligned currents is the process of energy conversion from thermal to electromagnetic
There are two types of dynamo processes, the expanding slow mode and the contracting slow mode
The coupling of the dynamo and the field‐aligned current generator occurs commonly in a specific spatial configuration
This paper studies quantitative properties of a multiple-worker firm search/matching model and investigates how worker transition rates and job flow rates are interrelated. We show that allowing for ...job-to-job transitions in the model is essential to simultaneously account for the cyclical features of worker transition rates and job flow rates. Important to this result are the distinctions between the job creation rate and the hiring rate and between the job destruction rate and the layoff rate. In the model without job-to-job transitions, these distinctions essentially disappear, thus making it impossible to simultaneously replicate the cyclical features of both labor market flows. web URL: http://www.sciencedirect.com/science/article/pii/S1094202516300102
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