142 research outputs found

    Variational Formulations for Electromagnetic Field and Charged-Particle Stream Configurations and Their Linearization

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    Two variational formulations for electromagnetic field and charged-particle stream configurations, in which both field and particles are described by the field-like variables suited for the problems of electrodynamics, are presented. One of them is directly obtained through slight modifications of Sturrock's original procedure but has a complicated form. The other is obtained through linearization of the preceding one and has a compact form. Both formulations lend themselves to straightforward derivation of the well-known energy-momentum tensor and/or its conservation law. Specifically the latter one is of academic interest because of its compact form. Moreover, as a proof of its practical usefulness the variational principle under the small-amplitude approximation is derived from it, which is known to provide a basis for the study of certain types of instability in plasmas. It is, however, hoped that it will find main applications in the electrodynamics problems concerned with large-amplitude behavior

    エストロゲン誘発ラットプロラクチン産生下垂体腺腫に対するブロモクリプチンおよびタモキシフェンの抗腫瘍効果

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    取得学位 : 博士(医学), 学位授与番号 : 医博乙第1369号, 学位授与年月日:平成8年2月5日,学位授与年:199

    Precipitation of calcium compounds onto rock surfaces in water with cementitious material

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    In this study, the precipitation of minerals onto rock surfaces was investigated to consider whether sealing of pores and cracks in rock can be accelerated. Cylindrical specimens were prepared and then kept in purified water with powders of high-strength and ultra-low-permeability concrete (HSULPC), which will be used to confine transuranic wastes in Japan. Then, the rock specimens were weighed and the surfaces of rock specimens were inspected under a microscope. It was recognized that precipitation occurred on the surface of the rock specimens. It was also shown that precipitation did not occur on rock specimens kept in water without HSULPC. The weight of all specimens stored in HSULPC increased, and the observed weight change was larger for rocks with higher porosities. It is concluded that precipitation of minerals occurs on the rock surface when the rock is kept in water with HSULPC powders. From the results obtained in this study, it is suggested that the sealing of pores and cracks in rock can be accelerated by the precipitation of calcium compounds using HSULPC. It is concluded that HSULPC is useful for underground radioactive waste disposal

    Salmonella osteomyelitis of the distal radius in a healthy young adult patient : Report of a rare case and literature review

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    Salmonella osteomyelitis of the radius in a healthy individual is very rare. We present such a case involving the distal radius of a healthy 23-year-old man without underlying disease or possible episode. He had right wrist pain for approximately 3 years, and osteolytic lesion was seen in the right distal radius. He underwent surgical treatment, and salmonella was isolated from pus in the lesion. Postoperative antibiotics successfully treated his infection. He had no sign of recurrence, but the point of entry for infection remains unknown

    Long-term Survival with a Rare Advanced Primary Gastrointestinal Malignant Melanoma Treated with Laparoscopic Surgery/Immune Checkpoint Inhibitor

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    Targeted therapies for malignant melanoma have improved patients’ prognoses. A primary gastrointestinal malignant melanoma is very rare, with no standard treatment strategy. We treated a 78-year-old Japanese female with advanced primary gastrointestinal melanoma of the descending colon and gallbladder. We administered a multidisciplinary treatment: surgical resection of the descending colon and gallbladder tumors, resection of the metastatic lymph nodes behind the pancreas head, and immune checkpoint antibody-blockade therapy (nivolumab) for ~4 years. PET/CT demonstrated no recurrent lesion for > 3 years. Multidisciplinary therapies (e.g., surgery, chemotherapy, radiotherapy, target therapy, and immune checkpoint antibody-blockade therapy) can successfully treat primary gastrointestinal malignant melanoma

    Free-Floating planet Mass Function from MOA-II 9-year survey towards the Galactic Bulge

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    We present the first measurement of the mass function of free-floating planets (FFP) or very wide orbit planets down to an Earth mass, from the MOA-II microlensing survey in 2006-2014. Six events are likely to be due to planets with Einstein radius crossing times, tE<0.5t_{\rm E}<0.5days, and the shortest has tE=0.057±0.016t_{\rm E} = 0.057\pm 0.016days and an angular Einstein radius of θE=0.90±0.14μ\theta_{\rm E} = 0.90\pm 0.14\muas. We measure the detection efficiency depending on both tEt_{\rm E} and θE\theta_{\rm E} with image level simulations for the first time. These short events are well modeled by a power-law mass function, dN4/dlogM=(2.181.40+0.52)×(M/8M)α4dN_4/d\log M = (2.18^{+0.52}_{-1.40})\times (M/8\,M_\oplus)^{-\alpha_4} dex1^{-1}star1^{-1} with α4=0.960.27+0.47\alpha_4 = 0.96^{+0.47}_{-0.27} for M/M<0.02M/M_\odot < 0.02. This implies a total of f=2113+23f= 21^{+23}_{-13} FFP or very wide orbit planets of mass 0.33<M/M<66600.33<M/M_\oplus < 6660 per star, with a total mass of 8047+73M80^{+73}_{-47} M_\oplus per star. The number of FFPs is 1913+2319_{-13}^{+23} times the number of planets in wide orbits (beyond the snow line), while the total masses are of the same order. This suggests that the FFPs have been ejected from bound planetary systems that may have had an initial mass function with a power-law index of α0.9\alpha\sim 0.9, which would imply a total mass of 17152+80M171_{-52}^{+80} M_\oplus star1^{-1}. This model predicts that Roman Space Telescope will detect 988566+1848988^{+1848}_{-566} FFPs with masses down to that of Mars (including 575424+1733575^{+1733}_{ -424} with 0.1M/M10.1 \le M/M_\oplus \le 1). The Sumi(2011) large Jupiter-mass FFP population is excluded.Comment: 17 pages, 7 figures, accepted for publication in A

    Brown dwarf companions in binaries detected from the 2021 season high-cadence microlensing surveys

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    As a part of the project aiming to build a homogeneous sample of binary-lens (2L1S) events containing brown-dwarf (BD) companions, we investigate the 2021 season microlensing data collected by the Korea Microlensing Telescope Network (KMTNet) survey. For this purpose, we first identify 2L1S events by conducting systematic analyses of anomalous lensing events. We then select candidate BD-companion events by applying the criterion that the mass ratio between the lens components is less than qth0.1q_{\rm th}\sim 0.1. From this procedure, we find four binary-lens events including KMT-2021-BLG-0588, KMT-2021-BLG-1110, KMT-2021-BLG-1643, and KMT-2021-BLG-1770, for which the estimated mass ratios are q0.10q\sim 0.10, 0.07, 0.08, and 0.15, respectively. The event KMT-2021-BLG-1770 is selected as a candidate despite the fact that the mass ratio is slightly greater than qthq_{\rm th} because the lens mass expected from the measured short time scale of the event, tE7.6t_{\rm E}\sim 7.6~days, is small. From the Bayesian analyses, we estimate that the primary and companion masses are (M1/M,M2/M)=(0.540.24+0.31,0.0530.023+0.031)(M_1/M_\odot, M_2/M_\odot)= (0.54^{+0.31}_{-0.24}, 0.053^{+0.031}_{-0.023}) for KMT-2021-BLG-0588L, (0.740.35+0.27,0.0550.026+0.020)(0.74^{+0.27}_{-0.35}, 0.055^{+0.020}_{-0.026}) for KMT-2021-BLG-1110L, (0.730.17+0.24,0.0610.014+0.020)(0.73^{+0.24}_{-0.17}, 0.061^{+0.020}_{-0.014}) for KMT-2021-BLG-1643L, and (0.130.07+0.18,0.0200.011+0.028)(0.13^{+0.18}_{-0.07}, 0.020^{+0.028}_{-0.011}) for KMT-2021-BLG-1770L. It is estimated that the probabilities of the lens companions being in the BD mass range are 82\%, 85\%, 91\%, and 59\% for the individual events. For confirming the BD nature of the lens companions found in this and previous works by directly imaging the lenses from future high-resolution adaptive-optics (AO) followup observations, we provide the lens-source separations expected in 2030, which is an approximate year of the first AO light on 30~m class telescopes.Comment: 11 pages, 10 tables, 8 figure

    KMT-2021-BLG-1150Lb: Microlensing planet detected through a densely covered planetary-caustic signal

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    Recently, there have been reports of various types of degeneracies in the interpretation of planetary signals induced by planetary caustics. In this work, we check whether such degeneracies persist in the case of well-covered signals by analyzing the lensing event KMT-2021-BLG-1150, for which the light curve exhibits a densely and continuously covered short-term anomaly. In order to identify degenerate solutions, we thoroughly investigate the parameter space by conducting dense grid searches for the lensing parameters. We then check the severity of the degeneracy among the identified solutions. We identify a pair of planetary solutions resulting from the well-known inner-outer degeneracy, and find that interpreting the anomaly is not subject to any degeneracy other than the inner-outer degeneracy. The measured parameters of the planet separation (normalized to the Einstein radius) and mass ratio between the lens components are (s,q)in(1.297,1.10×103)(s, q)_{\rm in}\sim (1.297, 1.10\times 10^{-3}) for the inner solution and (s,q)out(1.242,1.15×103)(s, q)_{\rm out}\sim (1.242, 1.15\times 10^{-3}) for the outer solution. According to a Bayesian estimation, the lens is a planetary system consisting of a planet with a mass Mp=0.880.36+0.38 MJM_{\rm p}=0.88^{+0.38}_{-0.36}~M_{\rm J} and its host with a mass Mh=0.730.30+0.32 MM_{\rm h}=0.73^{+0.32}_{-0.30}~M_\odot lying toward the Galactic center at a distance DL=3.81.2+1.3D_{\rm L} =3.8^{+1.3}_{-1.2}~kpc. By conducting analyses using mock data sets prepared to mimic those obtained with data gaps and under various observational cadences, it is found that gaps in data can result in various degenerate solutions, while the observational cadence does not pose a serious degeneracy problem as long as the anomaly feature can be delineated.Comment: 9 pages, 8 figure
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