1,174 research outputs found

    Explicit examples of DIM constraints for network matrix models

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    Dotsenko-Fateev and Chern-Simons matrix models, which describe Nekrasov functions for SYM theories in different dimensions, are all incorporated into network matrix models with the hidden Ding-Iohara-Miki (DIM) symmetry. This lifting is especially simple for what we call balanced networks. Then, the Ward identities (known under the names of Virasoro/W-constraints or loop equations or regularity condition for qq-characters) are also promoted to the DIM level, where they all become corollaries of a single identity.Comment: 46 page

    A case of Epstein-Barr virus–associated hemophagocytic lymphohistiocytosis with severe cardiac complications

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    BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a life threatening hematological disorder associated with severe systemic inflammation caused by an uncontrolled and ineffective immune response resulting in cytokine storm. Epstein-Barr virus (EBV) is the most common infectious agent in patients with the viral-associated HLH. Limited numbers of cases with cardiac complication have been demonstrated in other viral-associated HLH patients. Herein, we report a pediatric case of severe EBV-associated HLH with cardiac complications. CASE PRESENTATION: A previously healthy 4-year-old Japanese female was admitted to a local hospital with a four day history of fever. Despite antibiotic treatment, her fever persisted to day 7 of the illness. Finally, the diagnosis of HLH was confirmed by fulfilling diagnostic criteria for HLH and pathological analysis of bone marrow aspiration. Real-time PCR detected a high copy number of EBV DNA in the peripheral blood mononuclear cells (PBMCs) at the time of hospital admission. During treatment according to HLH-2004 protocol, sudden cardiopulmonary arrest (CPA) occurred on day 30 of the illness and immediate resuscitation was successful. Acute myocarditis was considered the cause of the CPA. Although the treatment regimen was completed on day 88 of the illness, a remarkably high copy number of EBV DNA was still detected in her PBMCs. Based on our flow cytometric in situ hybridization analysis that revealed EBV infection of only B lymphocytes, we decided to administer rituximab to control the abnormal EBV infection. Afterwards the amount of EBV DNA decreased gradually to undetectable level on day 130 of the illness. Unfortunately, a coronary artery aneurysm was discovered at the left main coronary artery on day 180 of the illness. Finally, the patient was discharged from the hospital on day 203 of the illness without sequelae except for a coronary aneurysm. CONCLUSIONS: In this case report, EBV-HLH was complicated with cardiac symptoms such as myocarditis and coronary artery aneurysm. Although remarkably high copy number of EBV DNA was detected in PBMCs after completion of the HLH-2004 protocol, rituximab treatment resulted in a dramatic decrease of EBV DNA to undetectable levels. Rituximab treatment might have been beneficial for the patient’s survival

    Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VI: The Sixth Year (2013-2014)

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    Continuing the project described by Kato et al. (2009, PASJ, 61, S395, arXiv:0905.1757), we collected times of superhump maxima for 56 SU UMa-type dwarf novae mainly observed during the 2013-2014 season and characterized these objects. We detected negative superhumps in VW Hyi and indicated that the low number of normal outbursts in some supercycle can be interpreted as a result of the disk tilt. This finding, combined with the Kepler observation of V1504 Cyg and V344 Lyr, suggests that the disk tilt is responsible for modulating the outburst pattern in SU UMa-type dwarf novae. We also studied the deeply eclipsing WZ Sge-type dwarf nova MASTER OT J005740.99+443101.5 and found evidence of a sharp eclipse during the phase of early superhumps. The profile can be reproduced by a combination of the eclipse of the axisymmetric disk and the uneclipsed light source of early superhumps. This finding confirms the lack of evince of a greatly enhanced hot spot during the early stage of WZ Sge-type outburst. We detected growing (stage A) superhumps in MN Dra and give a suggestion that some of SU UMa-type dwarf novae situated near the critical condition of tidal instability may show long-lasting stage A superhumps. The large negative period derivatives reported in such systems can be understood a result of the combination of stage A and B superhumps. The WZ Sge-type dwarf novae AL Com and ASASSN-13ck showed a long-lasting (plateau-type) rebrightening. In the early phase of the rebrightening, both objects showed a precursor-like outburst, suggesting that the long-lasting rebrightening is triggered by a precursor outburst.Comment: 73 pages, 88 figures, accepted for publication in PAS

    Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

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    We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte
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