276 research outputs found

    Nucleon structure from 2+1 flavor lattice QCD near the physical point

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    We present an update on our results of nucleon form factors measured on a large-volume lattice (8.1fm)4(8.1\rm{fm})^4 at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared O(a)\mathcal{O}(a) improved Wilson quark action and Iwasaki gauge action at β=1.82\beta = 1.82, which corresponds to the lattice spacing of 0.085 fm. The pion mass at the simulation point is about 145 MeV. We determine the iso- vector electric radius and magnetic moment from nucleon electric (GEG_E) and magnetic (GMG_M) form factors. We also report on preliminary results of the axial-vector (FAF_A), induced pseudo-scalar (FPF_P) and pseudo-scalar (GPG_P) form factors in order to verify the axial Ward- Takahashi identity in terms of the nucleon matrix elements, which may be called as the generalized Goldberger-Treiman relation.Comment: 8 pages, 12 figures; talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai

    Endoscopic thoracic sympathicotomy for Raynaud's phenomenon

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    AbstractPurpose: For many years, thoracic sympathectomy via open surgery was not used to treat Raynaud's phenomenon because of the invasiveness of this procedure and the poor long-term outcomes associated with it. However, with the introduction of endoscopic surgery, thoracic sympathectomy (or sympathicotomy) has been performed by some surgeons as a less invasive surgical option for patients with Raynaud's phenomenon. The less invasive procedure has the possibility of emphasizing merits of sympathectomy. The purpose of this study was to reevaluate the efficacy of sympathicotomy for Raynaud's phenomenon with endoscopic technique and its range of applicability. Methods: Between December 1992 and August 2001, endoscopic thoracic sympathicotomy (ETS) was performed in 28 patients with Raynaud's phenomenon (of a total of 502 patients with autonomic disorders who underwent ETS) at National Kanazawa Hospital. We considered indications for surgical treatment of Raynaud's phenomenon to include severe chronic symptoms or nonhealing digital ulceration refractory to intensive medical therapy. All patients were mailed a self-assessment questionnaire after surgery to determine the immediate and long-term results of the procedure. Data from both initial and long-term follow-up examinations were obtained. Results: Fifty-four ETS procedures were performed in 28 patients. No operative mortality was seen, and no occurrence of major complications necessitated open surgery. Initial resolution or improvement of symptoms was achieved in 26 of 28 patients (92.9%). However, later in the postoperative period, symptoms recurred in 23 of 28 patients (82.1%), although no recurrence of digital ulceration was seen throughout our observation. At the final follow-up examination (median follow-up period, 62.5 months), 25 patients (89.3%) reported overall improvement of the frequency and severity of their symptoms. Conclusion: Despite the high rate of recurrence, ETS clearly produced a high rate of initial relief. ETS did indeed promote healing of digital ulcers, and the procedure shows potential for reducing the severity of refractory symptoms. We consider ETS to be the method of choice for treatment of severe or refractory Raynaud's phenomenon, and especially for Raynaud's involving digital ulcer, because of its safety and efficacy. (J Vasc Surg 2002;36:57-61.

    Towards the continuum limit of nucleon form factors at the physical point using lattice QCD

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    We present results for the axial charge and root-mean-square (RMS) radii of the nucleon obtained from 2+1 flavor lattice QCD at the physical point with a large spatial extent of about 10 fm. Our calculations are performed with the PACS10 gauge configurations generated by the PACS Collaboration with the six stout-smeared O(a)O(a) improved Wilson-clover quark action and Iwasaki gauge action at β\beta = 1.82 and 2.00 corresponding to lattice spacings of 0.085 fm and 0.063 fm respectively. We first evaluate the value of gA/gVg_A/g_V , which is not renormalized in the continuum limit and thus ends up with the renormalized axial charge. Moreover, we also calculate the nucleon elastic form factors and determine three kinds of isovector RMS radii such as electric, magnetic and axial ones at the two lattice spacings. We finally discuss the discretization uncertainties on renormalized axial charge and isovector RMS radii towards the continuum limit.Comment: 9 pages, 2 figures, Proceeding for the 39th International Symposium on Lattice Field Theory, 8th-13th August 2022, Bonn, German

    Shock-wave propagation in supercritical CO2 induced by nanosecond-pulsed arc plasma

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    Shock waves generated by arc plasma in supercritical (SC) CO2 have the potential to create novel reaction fields. However, there have been few studies of shock-wave characteristics in SC-CO2. This study provides the results of visualization of shock-wave propagation in SC-CO2 generated by nanosecond-pulsed arc plasma. A propagating cylindrical shock wave originating from a discharge channel was observed using time-resolved shadowgraph imaging. The shock wave separated from the cylindrical dark-region induced by pulsed arc plasma within 64 nanoseconds. The Mach numbers of the shock waves were investigated against the medium density of the CO2 ranging from a high-pressure gas phase to the SC phase. The Mach number reached a local maximum at the critical CO2 density level. The anomaly in the Mach number can be explained by the local maximum of the specific heat capacity ratio of the CO2 at close to the critical condition of SC-CO2

    Lipomatous Pseudohypertrophy of the Pancreas Taking the Form of Huge Massive Lesion of the Pancreatic Head

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    A 70-year-old woman presented with hypogastric pain. Computed tomography and magnetic resonance imaging revealed a retroperitoneal tumor 18.0 cm in diameter with fatty tissue density, ventrally compressing the pancreatic head. We suspected a well-differentiated liposarcoma compressing the pancreas. At laparotomy, the tumor mass was the size of an infant's head; its center was located in the area corresponding to the pancreatic uncus. It was continuous with the pancreatic parenchyma through a poorly demarcated border, and we resected as much of the tumor mass as possible while conserving the pancreatic capsule. Histopathological examination indicated lipomatous pseudohypertrophy of the pancreas with proliferation of mature fatty tissue as the main constituent. At the periphery, islands of acinar tissue were retained among the fatty infiltration, which also contained branches of the pancreatic duct and islets of Langerhans. Previous reports have stated that this disorder only causes fatty replacements throughout the pancreas or in the pancreatic body and tail; however, in this patient, imaging and macroscopic examination revealed no fatty replacements in the pancreatic body and tail. We report this case, which we consider extremely rare, along with a brief review of the literature
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