Time Evolution of Relativistic Force-Free Fields Connecting a Neutron Star and its Disk

We study the magnetic interaction between a neutron star and its disk by solving the time-dependent relativistic force-free equations. At the initial state, we assume that the dipole magnetic field of the neutron star connects the neutron star and its equatorial disk, which deeply enters into the magnetosphere of the neutron star. Magnetic fields are assumed to be frozen to the star and the disk. The rotation of the neutron star and the disk is imposed as boundary conditions. We apply Harten-Lax-van Leer (HLL) method to simulate the evolution of the star-disk system. We carry out simulations for (1) a disk inside the corotation radius, in which the disk rotates faster than the star, and (2) a disk outside the corotation radius, in which the neutron star rotates faster than the disk. Numerical results indicate that for both models, the magnetic field lines connecting the disk and the star inflate as they are twisted by the differential rotation between the disk and the star. When the twist angle exceeds pi radian, the magnetic field lines expand with speed close to the light speed. This mechanism can be the origin of relativistic outflows observed in binaries containing a neutron star.Comment: 10 pages, 6figures, accepted for publication in PAS

Stratigraphical Study of the Miocene Series in the Eastern Part of Tottori Prefecture, Southwest Japan

In this paper, the stratigraphy of the Miocene series distributed in the eastern part of Tottori Prefecture is described in detail, with some considerations on correlation and geologic history. The results obtained are summarized as follows. The eastern part of Tottori Prefecture occupies a part of the so-called Green Tuff region, and is characterized by the development of a thick series of Miocene volcanic and clastic rocks formed by strong volcanism and subsequent subsidence. The Miocene series is called the Tottori Group, and is divided into two formations, i. e., the lower Yazu and the upper Iwami Formation. The Yazu Formation is subdivided into the Koge Conglomer-ate Member below and the Kawabara Volcanic Member above, which are conformable with each other. The Koge Member is the basal conglomerate member of the Tottori Group. The Kawabara Member consists mainly of thick piles of volcanic rocks such as andesite lavas and andesitic to dacitic pyroclastics, with intercalation of layers of clastic sediments. The Iwami Formation has an unconformable relationship with the Yazu For-mation, and is lithologically subdivided into the Entsuji Conglomerate and Sandstone, Moroga Conglomerate, Fuganji Mudstone, Oda Andesite, Aragane Pyroclastic and Shichi-yama Sandstone and Mudstone Members. The first two members are interfingered with the lower part of the Fuganji Member, while the last three with the upper part of the Fuganji. The Entsuji and Moroga Members are composed mainly of alternating beds of conglomerate and sandstone. The Fuganji Member is made up of well-stratified mudstone, accompanied with parallel-laminated, fissile one in the lower part. The Oda and Aragane Members consist largely of thick accumulations of volcanic rocks such as andesite lavas and dacitic pyroclastics. The Shichiyama Member is represented by fine- to medium-grained sandstone, accompanied with mudstone and dacitic pyroclastic rocks. Two molluscan assemblages of relatively deep sea type, namely, the Acesta assem-blage below and the Propeamussium-Delectopecten assemblage above, are recognized in the main part of the Fuganji Member. Judging from the faunal and floral assemblages, as well as from the lithofacies, it is inferred that the sedimentary environment of the Iwami Formation changed from fresh-water condition to brackish-water or shallow marine one and further to the deeper sea. The main part of the Fuganji Member represents deposits of maximum transgression at Middle Miocene time. The northward tilting of the basement blocks controlled by the uplifting of the island arc has been revealed through the analysis of stratigraphic relationship, geologic structure and lateral change in lithofacies. The uplifting and tilting may be closely related not only to the migration of depocenters of the Miocene and Pliocene sedimentary basins toward the Sea of Japan but also to the longitudinal gravity faulting in horizontally tensional stress field. The initiative uplifting may have begun at Early Miocene time

Recent advances in the management of osteoporosis

There has been substantial progress in the management of patients with osteoporosis and the prevention of osteoporotic fractures. Currently available strong anti-resorptive agents are bisphosphonates and an anti-receptor activator of nuclear factor-kappa B ligand (RANKL) antibody, denosumab. Although bisphosphonates and denosumab both inhibit bone resorption and prevent vertebral and non-vertebral fractures, their mechanisms of action are different. Whereas bisphosphonates’ effects on bone mineral density and fracture peak around 3 to 5 years and become plateaued, those of denosumab are maintained for up to 10 years. There are differences in the modes of action of these two drugs. Bisphosphonates accumulate on the mineralized bone surface and are released by the acid environment under osteoclastic bone resorption, whereas denosumab is not accumulated on bone but directly binds RANKL and inhibits its binding to the receptor RANK. Thus, the reduction in denosumab concentration 4 to 6 months after injection may enable RANK to bind to RANKL, where it is highly expressed, such as in damaged bone regions. As anabolic agents, only teriparatide has been available for a long time, but abaloparatide, a synthetic analog of PTHrP(1–34), is currently under development. Because of the difference in the preferential binding conformations of PTH1 receptor between teriparatide and abaloparatide, the latter shows anabolic effects with fewer bone resorptive effects. Romosozumab, an anti-sclerostin antibody, inhibits the action of sclerostin, a canonical Wnt signal inhibitor secreted from osteocytes, and enhances canonical Wnt signaling. Romosozumab robustly increases vertebral and proximal femoral bone mineral density within 12 months and inhibits vertebral and clinical fractures in patients with osteoporosis by enhancing bone formation and inhibiting bone resorption. In this review, we summarize the recent advances in therapeutic agents for the treatment of osteoporosis and discuss future prospects with their use

Low-Resolution Spectrum of the Diffuse Galactic Light and 3.3 um PAH emission with AKARI InfraRed Camera

We first obtained the spectrum of the diffuse Galactic light (DGL) at general interstellar space in 1.8-5.3 um wavelength region with the low-resolution prism spectroscopy mode of the AKARI Infra-Red Camera (IRC) NIR channel. The 3.3 um PAH band is detected in the DGL spectrum at Galactic latitude |b| < 15 deg, and its correlations with the Galactic dust and gas are confirmed. The correlation between the 3.3 um PAH band and the thermal emission from the Galactic dust is expressed not by a simple linear correlation but by a relation with extinction. Using this correlation, the spectral shape of DGL at optically thin region (5 deg < |b| < 15 deg) was derived as a template spectrum. Assuming that the spectral shape of this template spectrum is uniform at any position, DGL spectrum can be estimated by scaling this template spectrum using the correlation between the 3.3 um PAH band and the thermal emission from the Galactic dust.Comment: 7 pages, 5 figures, accepted by Publications of the Astronomical Society of Japan (PASJ