Machine learning with systematic density-functional theory calculations: Application to melting temperatures of single and binary component solids

A combination of systematic density functional theory (DFT) calculations and machine learning techniques has a wide range of potential applications. This study presents an application of the combination of systematic DFT calculations and regression techniques to the prediction of the melting temperature for single and binary compounds. Here we adopt the ordinary least-squares regression (OLSR), partial least-squares regression (PLSR), support vector regression (SVR) and Gaussian process regression (GPR). Among the four kinds of regression techniques, the SVR provides the best prediction. In addition, the inclusion of physical properties computed by the DFT calculation to a set of predictor variables makes the prediction better. Finally, a simulation to find the highest melting temperature toward the efficient materials design using kriging is demonstrated. The kriging design finds the compound with the highest melting temperature much faster than random designs. This result may stimulate the application of kriging to efficient materials design for a broad range of applications

Multi-messenger signals of long-term core-collapse supernova simulations : synergetic observation strategies

The next Galactic supernova is expected to bring great opportunities for the direct detection of gravitational waves (GW), full flavor neutrinos, and multi-wavelength photons. To maximize the science return from such a rare event, it is essential to have established classes of possible situations and preparations for appropriate observations. To this end, we use a long-term numerical simulation of the core-collapse supernova (CCSN) of a 17 solar-mass red supergiant progenitor to self-consistently model the multi-messenger signals expected in GW, neutrino, and electromagnetic messengers. This supernova model takes into account the formation and evolution of a protoneutron star, neutrino-matter interaction, and neutrino transport, all within a two-dimensional shock hydrodynamics simulation. With this, we separately discuss three situations: (i) a CCSN at the Galactic Center, (ii) an extremely nearby CCSN within hundreds of parsecs, and (iii) a CCSN in nearby galaxies within several Mpc. These distance regimes necessitate different strategies for synergistic observations. In a Galactic CCSN, neutrinos provide strategic timing and pointing information. We explore how these in turn deliver an improvement in the sensitivity of GW analyses and help to guarantee observations of early electromagnetic signals. To facilitate the detection of multi-messenger signals of CCSNe in extremely nearby and extragalactic distances, we compile a list of nearby red supergiant candidates and a list of nearby galaxies with their expected CCSN rates. By exploring the sequential multi-messenger signals of a nearby CCSN, we discuss preparations for maximizing successful studies of such an unprecedented stirring event.Comment: Link to the online material (lists of nearby RSG candidates and local galaxies) is added, also available from http://th.nao.ac.jp/MEMBER/nakamura/2016multi/index.htm

Effects of gelation concentration on cyclic deformation behavior of κ-carrageenan hydrogels

The aim of this study is to elucidate the relationship between the network structure of κ-carrageenan hydrogels and their mechanical properties. First κ-carrageenan hydrogels have been prepared at different gelation concentrations, and then the mechanical behavior during four cyclic deformations has been examined at the same κ-carrageenan concentration. Young's modulus is higher for the gel prepared at 5 gL⁻¹ (C05) compared to that for the gel prepared at 30 gL⁻¹ (C30). C30 shows almost linear relation between the stress and the strain like an ideal rubber, while a residual strain appears in each cyclic deformation for C05. The extent of the residual strain depends on the maximum strain and the deformation speed, indicating that C05 deforms plastically to some extent. The residual strain for C05 decreases gradually even after a cyclic deformation and disappears in the case of a small strain as if there were a memory of the structure. The effects of the gelation concentration on the mechanical properties have been explained based on the network structure specific to κ-carrageenan hydrogels. The higher modulus for C05 has been attributed to the higher helix content and the plastic deformation of C05 to the loosely-aggregated crosslinks

Beneficial Xultophy Treatment from Medical and Social Points of View

The case is a 65-year-old male who has been treated for Type 2 diabetes mellitus (T2DM) for 26 years. He has no previous history of cerebral vascular accident (CVA) or coronary heart disease (CHD). He has been treated on insulin therapy, and recently his glucose variability became worse due to the irregular lifestyle. Then, diabetic treatment was changed to Xultophy, which consists of insulin degludec and liraglutide. Providing 16 units of Xultophy brought him a satisfactory daily profile of blood glucose, which seemed to be lower doses compared with the ordinary standard amount. Treatment of Xultophy seems to be effective and some discussion would be described from several points of view

Study on acoustical physical constants of ZnO single crystal using the ultrasonic microspectroscopy technology

2008 IEEE International Ultrasonics Symposium Proceeding

Pre-DECIGO can get the smoking gun to decide the astrophysical or cosmological origin of GW150914-like binary black holes

Pre-DECIGO consists of three spacecraft arranged in an equilateral triangle with 100km arm lengths orbiting 2000km above the surface of the earth. It is hoped that the launch date will be in the late 2020s. Pre-DECIGO has one clear target: binary black holes (BBHs) like GW150914 and GW151226. Pre-DECIGO can detect $\sim 30M_\odot-30M_\odot$ BBH mergers up to redshift $z\sim 30$. The cumulative event rate is $\sim 1.8\times 10^{5}\,{\rm events~yr^{-1}}$ in the Pop III origin model of BBHs like GW150914, and it saturates at $z\sim 10$, while in the primordial BBH (PBBH) model, the cumulative event rate is $\sim 3\times 10^{4}\,{\rm events~ yr^{-1}}$ at $z=30$ even if only $0.1\%$ of the dark matter consists of PBHs, and it is still increasing at $z=30$. In the Pop I/II model of BBHs, the cumulative event rate is $(3-10)\times10^{5}\,{\rm events~ yr^{-1}}$ and it saturates at $z \sim 6$. We present the requirements on orbit accuracy, drag free techniques, laser power, frequency stability, and interferometer test mass. For BBHs like GW150914 at 1Gpc, SNR$\sim 90$ is achieved with the definition of Pre-DECIGO in the $0.01-100$Hz band. Pre-DECIGO can measure the mass spectrum and the $z$-dependence of the merger rate to distinguish various models of BBHs like GW150914. Pre-DECIGO can also predict the direction of BBHs at $z=0.1$ with an accuracy of $\sim 0.3\,{\rm deg}^2$ and a merging time accuracy of $\sim 1$s at about a day before the merger so that ground-based GW detectors further developed at that time as well as electromagnetic follow-up observations can prepare for the detection of merger in advance. For intermediate mass BBHs at a large redshift $z > 10$, the QNM frequency after the merger can be within the Pre-DECIGO band so that the ringing tail can also be detectable to confirm the Einstein theory of general relativity with SNR$\sim 35$. [abridged]Comment: 17 pages, 10 figures, added some references, modifications to match the published version in PTE

Intermediate-Mass-Elements in Young Supernova Remnants Reveal Neutron Star Kicks by Asymmetric Explosions

The birth properties of neutron stars yield important information on the still debated physical processes that trigger the explosion and on intrinsic neutron-star physics. These properties include the high space velocities of young neutron stars with average values of several 100 km/s, whose underlying "kick" mechanism is not finally clarified. There are two competing possibilities that could accelerate NSs during their birth: anisotropic ejection of either stellar debris or neutrinos. We here present new evidence from X-ray measurements that chemical elements between silicon and calcium in six young gaseous supernova remnants are preferentially expelled opposite to the direction of neutron star motion. There is no correlation between the kick velocities and magnetic field strengths of these neutron stars. Our results support a hydrodynamic origin of neutron-star kicks connected to asymmetric explosive mass ejection, and they conflict with neutron-star acceleration scenarios that invoke anisotropic neutrino emission caused by particle and nuclear physics in combination with very strong neutron-star magnetic fields.Comment: 24 pages, 12 figures, accepted for publication in The Astrophysical Journa