Primordial Black Holes for the LIGO Events in the Axion-like Curvaton Model

We revise primordial black hole (PBH) formation in the axion-like curvaton model and investigate whether PBHs formed in this model can be the origin of the gravtitational wave (GW) signals detected by the Advanced LIGO. In this model, small-scale curvature perturbations with large amplitude are generated, which is essential for PBH formation. On the other hand, large curvature perturbations also become a source of primordial GWs by their second-order effects. Severe constraints are imposed on such GWs by pulsar timing array (PTA) experiments. We also check the consistency of the model with these constraints. In this analysis, it is important to take into account the effect of non-Gaussianity, which is generated easily in the curvaton model. We see that, if there are non-Gaussianities, the fixed amount of PBHs can be produced with a smaller amplitude of the primordial power spectrum.Comment: 25 pages, 8 figure

微分曲線解析および単粒子測定法によるリチウムイオン電池の劣化メカニズム解析

首都大学東京, 2018-9-30, 博士（工学）, 甲第868号首都大学東

Change of Temperature and Pressure in Dry and Green Douglas-Fir and Sugi Wood During Passive Impregnation Method

This work investigated pressure and temperature change in green and dry Douglas-fir and sugi wood during passive impregnation treatment with copper azole type B preservative at higher concentration. Temperature and pressure sensors were used in wood for obtaining temperature and pressure change data every 10 s during the preservative treatment. Gross preservative and X-ray fluorescence spectroscopy was used to obtain retention. Penetration was measured following the standard. Although temperature rise was steeper in green Douglas-fir, pressure was higher in green sugi. However, phenomena were similar for dry lumber of both species. Preservative retention was very high (6.63 kg/m3), and in most cases, it exceeded the requirements of permanent structural components in ground contact applications. Preservative penetration was almost 100% for all samples

Binary Neutron Stars in Quasi-equilibrium

Quasi-equilibrium sequences of binary neutron stars are constructed for a variety of equations of state in general relativity. Einstein's constraint equations in the Isenberg-Wilson-Mathews approximation are solved together with the relativistic equations of hydrostationary equilibrium under the assumption of irrotational flow. We focus on unequal-mass sequences as well as equal-mass sequences, and compare those results. We investigate the behavior of the binding energy and total angular momentum along a quasi-equilibrium sequence, the endpoint of sequences, and the orbital angular velocity as a function of time, changing the mass ratio, the total mass of the binary system, and the equation of state of a neutron star. It is found that the orbital angular velocity at the mass-shedding limit can be determined by an empirical formula derived from an analytic estimation. We also provide tables for 160 sequences which will be useful as a guideline of numerical simulations for the inspiral and merger performed in the near future.Comment: 66 pages, 26 figures, 6 tables, aaste

Effects of Cerclage Cabling on Preventing Periprosthetic Femoral Fractures When Using Cementless Stems for Unstable Femoral Neck Fractures

Iwasa M., Ando W., Takashima K., et al. Effects of Cerclage Cabling on Preventing Periprosthetic Femoral Fractures When Using Cementless Stems for Unstable Femoral Neck Fractures. Journal of Arthroplasty , (2024); https://doi.org/10.1016/j.arth.2024.04.085.Background: Periprosthetic femoral fractures (PFFs) are serious complications in hip arthroplasty for femoral neck fractures. The rates of intraoperative (iPFFs) and postoperative PFFs (pPFFs) are higher in cementless stem cases than in cemented cases. This study aimed to investigate the effects of cerclage cabling on PFF prevention in cementless arthroplasty for femoral neck fractures. Methods: This retrospective study included 329 consecutive patients who underwent hip arthroplasty using a cementless stem for femoral neck fractures. A total of 159 and 170 patients were in the non-cabling and cabling groups, respectively. Patient characteristics were comparable in both groups. The PFF occurrence (iPFF and pPFF) rates, reoperation rates, operative time, and blood loss volume were compared between the groups. Results: The iPFF rate was significantly higher in the noncabling group (6.3%) than in the cabling group (0%, P <.001). The rate of pPFF was significantly higher in the non-cabling group (5.1%) than in the cabling group (0.6%; P =.016). All patients in the non-cabling group required reoperation (5.1%), whereas the patient in the cabling group was an ambulatory case and required no reoperation (0%, P =.003). No significant difference in either operative time or blood loss volume was observed between the non-cabling (50 minutes, 133 mL) and cabling (52 minutes, P =.244; 149 mL, P =.212, respectively) groups. Conclusions: When a cementless stem is used to treat unstable femoral neck fractures, cerclage cabling effectively prevents iPPF and pPPF without increasing surgical time or blood loss volume