2,178 research outputs found

    Black Holes at the LHC: Progress since 2002

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    We review the recent noticeable progresses in black hole physics focusing on the up-coming super-collider, the LHC. We discuss the classical formation of black holes by particle collision, the greybody factors for higher dimensional rotating black holes, the deep implications of black hole physics to the `energy-distance' relation, the security issues of the LHC associated with black hole formation and the newly developed Monte-Carlo generators for black hole events.Comment: 6 pages, 10 figures, Plenary talk given at the 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY08), Seoul, Korea (June 16-21, 2008). To be published in the Conference Proceeding

    Inflation in the nonminimal theory with `K(phi)R' term

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    A class of inflationary models with the nonminimal coupling term `K(phi)R' is considered. We show that the successful inflation can take place if the ratio between the square of the nonminimal coupling term and the potential for the scalar goes asymptotically constant.Comment: 3 pages, 1 figure, Talk given at 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY08), Seoul, Korea, 16-21 Jun 200

    511 keV Ī³\gamma-ray emission from the galactic bulge by MeV millicharged dark matter

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    We propose a possible explanation for the recently observed anomalous 511 keV line with a new "millicharged" fermion. This new fermion is light [O(MeV){\cal O}({\rm MeV})]. Nevertheless, it has never been observed by any collider experiments by virtue of its tiny electromagnetic charge Ļµe\epsilon e. In particular, we constrain parameters of this millicharged particle if the 511 keV cosmic Ī³\gamma-ray emission from the galactic bulge is due to positron production from this new particle.Comment: 3 pages, 1 figure, A talk given by J.C.Park at the 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY08), Seoul, Korea, June 16-21, 200

    Strain-gradient-induced magnetic anisotropy in straight-stripe mixed-phase bismuth ferrites: An insight into flexomagnetic phenomenon

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    Implementation of antiferromagnetic compounds as active elements in spintronics has been hindered by their insensitive nature against external perturbations which causes difficulties in switching among different antiferromagnetic spin configurations. Electrically-controllable strain gradient can become a key parameter to tune the antiferromagnetic states of multiferroic materials. We have discovered a correlation between an electrically-written straight-stripe mixed-phase boundary and an in-plane antiferromagnetic spin axis in highly-elongated La-5%-doped BiFeO3_{3} thin films by performing polarization-dependent photoemission electron microscopy in conjunction with cluster model calculations. Model Hamiltonian calculation for the single-ion anisotropy including the spin-orbit interaction has been performed to figure out the physical origin of the link between the strain gradient present in the mixed phase area and its antiferromagnetic spin axis. Our findings enable estimation of the strain-gradient-induced magnetic anisotropy energy per Fe ion at around 5Ɨ\times10āˆ’12^{-12} eV m, and provide a new pathway towards an electric-field-induced 90āˆ˜^{\circ} rotation of antiferromagnetic spin axis at room temperature by flexomagnetism.Comment: 32 pages, 5 figure

    The Spectrum of Epstein-Barr Virus-Associated Lymphoproliferative Disease in Korea: Incidence of Disease Entities by Age Groups

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    This study is to identify the spectrum of Epstein-Barr virus (EBV)-positive lymphoproliferative diseases (LPD) and relationships between these diseases in Korea. The EBV status and clinicopathology of 764 patients, including acute EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), chronic active EBV (CAEBV) infections, B-LPD arising in chronic latent EBV infection, T & natural killer (NK) cell non-Hodgkin's lymphomas (NHL), B-NHLs, and Hodgkin's lymphomas (HD), were analyzed. T or NK cell NHLs were the most common forms of EBV-positive NHLs (107/167, 64%); among these, nasal-type NK/T cell lymphomas were the most common (89/107, 83%). According to the age, Burkitt's lymphoma was the most common in early childhood; in teenagers, chronic (active) EBV infection-associated LPD was the most common type. The incidence of NK/T cell lymphoma began to increase from the twenties and formed the major type of EBV-associated tumor throughout life. Diffuse large B cell lymphoma formed the major type in the sixties and seventies. In conclusion, primary infections in early childhood are complicated by the development of CAEBV infections that are main predisposing factors for EBV-associated T or NK cell malignancies in young adults. In old patients, decreased immunity associated with old age and environmental cofactors may provoke the development of peripheral T cell lymphoma, unspecified, and diffuse large B cell lymphoma

    Symptomatic epidural gas cyst treated with epidural block and percutaneous needle aspiration -A case report-

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    A 68-year-old woman suffered from lower back and radiating pain on her right buttock and posterior calf. Axial magnetic resonance imaging showed a 7 Ɨ 7 mm nodular lesion (T1 and, T2 low signal intensity) at the epidural space between the L5-S1 level and computed tomography revealed it was an epidural gas cyst. The authors performed an epidural block and percutaneous needle aspiration of the epidural gas cyst. The patient showed almost complete resolution of symptoms one year later. The authors suggest that an epidural nerve block with needle aspiration of a gas cyst could be an alternative treatment option for patients with a symptomatic epidural gas cyst before surgery

    Mediastinal Single Nodal Relapse of a Nasal Nk/T cell Lymphoma

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    A nasal NK/T cell lymphoma is a very aggressive form of lymphoma. Patterns of relapse after treatment have not been systematically evaluated, and mediastinal nodal relapse at a primary site has never been documented. We describe here a 40-year old man who presented with a nasal obstruction caused by a protruding mass that was identified as a nasal NK/T cell lymphoma. The initial work-up, including chest and abdominopelvic computed tomography (CT) and positron emission tomography (PET), showed no regional or distant metastasis. A CT scan performed following three cycles of chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) showed that the mass had nearly disappeared. Radiation therapy undertaken following chemotherapy was given to the primary site. However, PET performed following radiotherapy revealed a single mediastinal lymphadenopathy, with no evidence of residual tumor in the nasal cavity. A biopsy using video-assisted thoracoscopy (VATS) showed the presence of a recurrent NK/T cell lymphoma with an immunophenotype identical to that of the primary nasal lymphoma. An additional three cycles of CHOP chemotherapy were administered, and the patient remains alive, with no evidence of disease 30 months after the initial relapse. These findings indicate that early detection with PET and prompt surgical excision with the use of VATS can lead to successful treatment of a relapsed nasal NK/T cell lymphoma
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