346 research outputs found

    Unified picture of Q-balls and boson stars via catastrophe theory

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    We make an analysis of Q-balls and boson stars using catastrophe theory, as an extension of the previous work on Q-balls in flat spacetime. We adopt the potential V3(ϕ)=m22ϕ2μϕ3+λϕ4V_3(\phi)={m^2\over2}\phi^2-\mu\phi^3+\lambda\phi^4 for Q-balls and that with μ=0\mu =0 for boson stars. For solutions with grr11|g^{rr}-1|\sim 1 at its peak, stability of Q-balls has been lost regardless of the potential parameters. As a result, phase relations, such as a Q-ball charge versus a total Hamiltonian energy, approach those of boson stars, which tell us an unified picture of Q-balls and boson stars.Comment: 10 pages, 13 figure

    Internal structure of Skyrme black hole

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    We consider the internal structure of the Skyrme black hole under a static and spherically symmetric ansatz. $@u8(Be concentrate on solutions with the node number one and with the "winding" number zero, where there exist two solutions for each horizon radius; one solution is stable and the other is unstable against linear perturbation. We find that a generic solution exhibits an oscillating behavior near the sigularity, as similar to a solution in the Einstein-Yang-Mills (EYM) system, independently to stability of the solution. Comparing it with that in the EYM system, this oscillation becomes mild because of the mass term of the Skyrme field. We also find Schwarzschild-like exceptional solutions where no oscillating behavior is seen. Contrary to the EYM system where there is one such solution branch if the node number is fixed, there are two branches corresponding to the stable and the unstable ones.Comment: 5 pages, 4 figures, some contents adde

    An approach to teaching a computer programming language

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    The 9th World Conference on Continuing Engineering Education, WCCEE 2004, slides ; Place : Tokyo, Japan ; Date : May 16-19, 200

    レーザースペックルフローグラフィーを用いて測定した硝子体手術の術前、術中、術後の眼血流

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    BACKGROUND AND OBJECTIVE: Vitrectomy markedly alters the intraocular milieu, which can then affect the physiology of the retina and choroid. This study investigates whether vitrectomy also alters ocular blood flow as determined by laser speckle flowgraphy (LSFG). PATIENTS AND METHODS: Twenty eyes of 20 patients that underwent vitrectomy for idiopathic macular hole or epiretinal membrane were studied. Standard 23-gauge microincision vitreous surgery was performed. Ocular blood flow of the optic nerve head, retinal vessels, and choroid was determined by LSGF before, during, and 2 weeks and 1 month after vitrectomy. RESULTS: Postoperative blood flow of the optic nerve head, retinal vessels, and choroid did not differ significantly from preoperative values. Intraoperative blood flow of the optic nerve head and retinal vessels decreased significantly from baseline with increasing infusion pressure from 20 mm Hg to 40 mm Hg (P < .01), and choroidal blood flow decreased significantly when the infusion pressure increased from 8 mm Hg to 20 mm Hg and from 20 mm Hg to 40 mm Hg (both P < .01). CONCLUSION: Blood flow did not differ significantly postoperatively versus preoperatively, but it was significantly reduced during vitrectomy with increasing infusion pressure. Careful attention should be paid to infusion pressure during vitrectomy.博士(医学)・乙第1368号・平成27年11月27日Copyright ©2014, SLACK Incorporated. All Rights Reserved.The definitive version is available at " http://dx.doi.org/10.3928/23258160-20140306-04

    Resectable hepatoblastoma with tumor thrombus extending into the right atrium after chemotherapy: A case report

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    AbstractHepatoblastoma with intraatrial tumor thrombus is relatively rare. We report a case of hepatoblastoma with tumor thrombus extending into the right atrium, which responded well to chemotherapy and was resected using extracorporeal circulation. A 4-year-old girl was referred to our hospital because of abdominal distention and tenderness. A computed tomography (CT) scan showed a large tumor occupying the left 3 segments of the liver with tumor thrombus extending into the right atrium. There was also a small intrahepatic metastasis in the right lobe of the liver. She was diagnosed with hepatoblastoma on the basis of the results of open biopsy. Neoadjuvant chemotherapy with an intense CDDP-based regimen was performed. The tumor responded well to chemotherapy, and intrahepatic metastasis became undetectable on CT scan, although the tumor thrombus remained in the right atrium. After 7 courses of chemotherapy, we performed resection using extracorporeal circulation. The postoperative course was uneventful, and adjuvant chemotherapy was started 10 days after the operation. Her serum alpha-fetoprotein (AFP) level decreased to the normal range, and she was free of disease for 1 year after the operation. Tumor resection using extracorporeal circulation can be performed safely and is justified in patients with intraatrial tumor thrombus

    The fate of Reissner-Nortstr\"{o}m black hole in the Einstein-Yang-Mills-Higgs system

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    We study about an evaporating process of black holes in SO(3) Einstein-Yang-Mills-Higgs system. We consider a massless scalar field which couple neither with the Yang-Mills field nor with the Higgs field surrounding the black hole. We discuss differences in evaporating rate between a monopole black hole and a Reissner-Nortstr\"{o}m (RN) black hole.Comment: 9 pages, 8 figure

    Equivalence of black hole thermodynamics between a generalized theory of gravity and the Einstein theory

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    We analyze black hole thermodynamics in a generalized theory of gravity whose Lagrangian is an arbitrary function of the metric, the Ricci tensor and a scalar field. We can convert the theory into the Einstein frame via a "Legendre" transformation or a conformal transformation. We calculate thermodynamical variables both in the original frame and in the Einstein frame, following the Iyer--Wald definition which satisfies the first law of thermodynamics. We show that all thermodynamical variables defined in the original frame are the same as those in the Einstein frame, if the spacetimes in both frames are asymptotically flat, regular and possess event horizons with non-zero temperatures. This result may be useful to study whether the second law is still valid in the generalized theory of gravity.Comment: 14 pages, no figure
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