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- Martin, P., et al.
(author)
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Overview of the RFX-mod fusion science programme
- 2013
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In: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 53:10, s. 104018-
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Research review (peer-reviewed)abstract
- This paper reports the highlights of the RFX-mod fusion science programme since the last 2010 IAEA Fusion Energy Conference. The RFX-mod fusion science programme focused on two main goals: exploring the fusion potential of the reversed field pinch (RFP) magnetic configuration and contributing to the solution of key science and technology problems in the roadmap to ITER. Active control of several plasma parameters has been a key tool in this endeavour. New upgrades on the system for active control of magnetohydrodynamic (MHD) stability are underway and will be presented in this paper. Unique among the existing fusion devices, RFX-mod has been operated both as an RFP and as a tokamak. The latter operation has allowed the exploration of edge safety factor q edge < 2 with active control of MHD stability and studies concerning basic energy and flow transport mechanisms. Strong interaction has continued with the stellarator community in particular on the physics of helical states and on three-dimensional codes.
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2. |
- Carbone, V, et al.
(author)
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To what extent can dynamical models describe statistical features of turbulent flows?
- 2002
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In: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 58:3, s. 349-355
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Journal article (peer-reviewed)abstract
- Statistical features of "bursty" behaviour in charged and neutral fluid turbulence are compared to statistics of intermittent events in a GOY shell model, and avalanches in different models of Self-Organized Criticality (SOC). It is found that inter-burst times show a power law distribution for turbulent samples and for the shell model, a property which is shared only in a particular case of the running sandpile model. The breakdown of self-similarity generated by isolated events observed in the turbulent samples is well reproduced by the shell model, while it is absent in all SOC models considered. On this base, we conclude that SOC models are not adequate to mimic fluid turbulence, while the GOY shell model constitutes a better candidate to describe the gross features of turbulence.
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4. |
- Sorriso-Valvo, Luca, et al.
(author)
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Intermittency in plasma turbulence
- 2001
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In: Planetary and Space Science. - 0032-0633 .- 1873-5088. ; 49:12, s. 1193-1200
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Journal article (peer-reviewed)
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6. |
- Carbone, V, et al.
(author)
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Intermittency and turbulence in a magnetically confined fusion plasma
- 2000
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In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - : American Physical Society (APS). - 1539-3755 .- 1550-2376. ; 62:1, s. R49-R52
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Journal article (peer-reviewed)abstract
- The intermittency of the magnetic turbulence in reversed field pinch plasmas was measured. The probability distribution functions of magnetic field differences were not scale invariant because the wings of these functions were more important as the scales become smaller. This phenomena was identified as a classical signature of intermittency. The scaling laws also appeared very close to the external wall of the confinement device.
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7. |
- Carbone, V., et al.
(author)
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Sign-Singularity of the Reduced Magnetic Helicity in the Solar Wind Plasma
- 2010
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 104:18, s. 181101-
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Journal article (peer-reviewed)abstract
- We investigate the scaling laws of a signed measure derived from the reduced magnetic helicity which has been determined from Cluster data in the solar wind. This quantifies the handedness of the magnetic field; namely, it can be related to the polarization of the magnetic field fluctuations (right or left hand). The measure results to be sign-singular; that is, we do not observe any scale-dependent effect at the ion-and at electron-cyclotron frequencies. Cancellations between right-and left-hand polarizations go on in the dispersive or dissipative range, beyond the electron-cyclotron frequency. This means that the mechanism responsible for the generation of the dispersive or dissipative range is rather insensitive to the polarization of the magnetic field fluctuations.
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8. |
- Greco, A., et al.
(author)
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The Complex Structure Of Magnetic Field Discontinuities In The Turbulent Solar Wind
- 2016
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In: Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 823:2
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Journal article (peer-reviewed)abstract
- Using high-resolution Cluster satellite observations and a multi-dimensional intermittency technique, we show that the magnetic discontinuities in the turbulent solar wind are connected through the spatial scales, going from proton down to electron scales. In some circumstances, their structure resembles the Harris equilibrium profile in plasmas. Observations are consistent with a scenario where many current layers develop in turbulence and where the outflow of these reconnection events are characterized by complex sub-proton networks of secondary islands, in a self-similar way. Although in the past these pictures have been speculated to be separately ubiquitous, through theories and simulations, the present work confirms that "reconnection in turbulence" and "turbulent reconnection" coexist in space plasmas.
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9. |
- Guigliano, Robert P, et al.
(author)
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Early versus delayed, provisional eptifibatide in acute coronary syndromes.
- 2009
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In: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 360:21, s. 2176-2190
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Journal article (peer-reviewed)abstract
- Background Glycoprotein IIb/IIIa inhibitors are indicated in patients with acute coronary syndromes who are undergoing an invasive procedure. The optimal timing of the initiation of such therapy is unknown. Methods We compared a strategy of early, routine administration of eptifibatide with delayed, provisional administration in 9492 patients who had acute coronary syndromes without ST-segment elevation and who were assigned to an invasive strategy. Patients were randomly assigned to receive either early eptifibatide (two boluses, each containing 180 µg per kilogram of body weight, administered 10 minutes apart, and a standard infusion 12 hours before angiography) or a matching placebo infusion with provisional use of eptifibatide after angiography (delayed eptifibatide). The primary efficacy end point was a composite of death, myocardial infarction, recurrent ischemia requiring urgent revascularization, or the occurrence of a thrombotic complication during percutaneous coronary intervention that required bolus therapy opposite to the initial study-group assignment ("thrombotic bailout") at 96 hours. The key secondary end point was a composite of death or myocardial infarction within the first 30 days. Key safety end points were bleeding and the need for transfusion within the first 120 hours after randomization. Results The primary end point occurred in 9.3% of patients in the early-eptifibatide group and in 10.0% in the delayed-eptifibatide group (odds ratio, 0.92; 95% confidence interval [CI], 0.80 to 1.06; P=0.23). At 30 days, the rate of death or myocardial infarction was 11.2% in the early-eptifibatide group, as compared with 12.3% in the delayed-eptifibatide group (odds ratio, 0.89; 95% CI, 0.79 to 1.01; P=0.08). Patients in the early-eptifibatide group had significantly higher rates of bleeding and red-cell transfusion. There was no significant difference between the two groups in rates of severe bleeding or nonhemorrhagic serious adverse events. Conclusions In patients who had acute coronary syndromes without ST-segment elevation, the use of eptifibatide 12 hours or more before angiography was not superior to the provisional use of eptifibatide after angiography. The early use of eptifibatide was associated with an increased risk of non–life-threatening bleeding and need for transfusion.
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10. |
- Harrington, Robert A., et al.
(author)
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The Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRA.CER) trial : study design and rationale
- 2009
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In: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 158:3, s. 327-334
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Journal article (peer-reviewed)abstract
- Background The protease-activated receptor 1 (PAR-1), the main platelet receptor for thrombin, represents a novel target for treatment of arterial thrombosis, and SCH 530348 is an orally active, selective, competitive PAR-1 antagonist. We designed TRA.CER to evaluate the efficacy and safety of SCH 530348 compared with placebo in addition to standard of care in patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS) and high-risk features. Trial design TRA.CER is a prospective, randomized, double-blind, multicenter, phase III trial with an original estimated sample size of 10,000 subjects. Our primary objective is to demonstrate that SCH 530348 in addition to standard of care will reduce the incidence of the composite of cardiovascular death, myocardial infarction (MI), stroke, recurrent ischemia with rehospitalization, and urgent coronary revascularization compared with standard of care alone. Our key secondary objective is to determine whether SCH 530348 will reduce the composite of cardiovascular death, MI, or stroke compared with standard of care alone. Secondary objectives related to safety are the composite of moderate and severe GUSTO bleeding and clinically significant TIMI bleeding. The trial will continue until a predetermined minimum number of centrally adjudicated primary and key secondary end point events have occurred and all subjects have participated in the study for at least I year. The TRA.CER trial is part of the large phase III SCH 530348 development program that includes a concomitant evaluation in secondary prevention. Conclusion TRA.CER will define efficacy and safety of the novel platelet PAR-1 inhibitor SCH 530348 in the treatment of high-risk patients with NSTE ACS in the setting of current treatment strategies.
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