Vortex Lattice in Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta} Well Above the First-Order Phase-Transition Boundary

Measurements of non-local in-plane resistance originating from transverse vortex-vortex correlations have been performed on a Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta} high-T_c superconductor in a magnetic field up to 9 T applied along the crystal c-axis. Our results demonstrate that a rigid vortex lattice does exist over a broad portion of the magnetic field -- temperature (H-T) phase diagram, well above the first-order transition boundary H_{FOT}(T). The results also provide evidence for the vortex lattice melting and vortex liquid decoupling phase transitions, occurring above the H_{FOT}(T).Comment: 14 pages, 10 figure

Quality of life in patients with stable coronary artery disease submitted to percutaneous, surgical, and medical therapies : a cohort study

Background: Clinical, surgical, and percutaneous strategies similarly prevent major cardiovascular events in patients with stable coronary artery disease (CAD). The possibility that these strategies have differential effects on healthrelated quality of life (HRQoL) has been debated, particularly in patients treated outside clinical trials. Methods: We assigned 454 patients diagnosed with CAD during an elective diagnostic coronary angiography to coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or optimal medical treatment (OMT), and followed them for an average of 5.2 ± 1.5 years. HRQoL was assessed using a validated Brazilian version of the 12-Item Short-Form Health Survey questionnaire. The association between therapeutic strategies and quality of life scores was tested using variance analysis and adjusted for confounders in a general linear model. Results: There were no differences in the mental component summary scores in the follow-up evaluation by therapeutic strategies: 51.4, 53.7, and 52.3 for OMT, PCI, and CABG, respectively. Physical component summary scores were higher in the PCI group than the CABG and OMT groups (46.4 vs. 42.9 and 43.8, respectively); however, these differences were no longer different after adjustment for confounding variables. Conclusion: In a long-term follow-up of patients with stable CAD, HRQoL did not differ in patients treated by medical, percutaneous, or surgical treatments

Effectiveness of clinical, surgical and percutaneous treatment to prevent cardiovascular events in patients referred for elective coronary angiography: an observational study

Purpose: To ascertain the most appropriate treatment for chronic, stable, coronary artery disease (CAD) in patients submitted to elective coronary angiography. Patients and Methods: A total of 814 patients included in the prospective cohort study were referred for elective coronary angiography and were followed up on average for 6±1.9 years. Main outcomes were all-cause death, cardiovascular death, non-fatal myocardial infarction (MI) and stroke and late revascularization and their combinations as major adverse cardiac and cerebral events (MACCE): MACCE-1 included cardiovascular death, nonfatal MI, and stroke; MACCE-2 was MACCE-1 plus late revascularization. Survival curves and adjusted Cox proportional hazard models were used to explore the association between the type of treatment and outcomes. Results: All-cause death was lower in participants submitted to percutaneous coronary intervention (PCI) (0.41, 0.16–1.03, P=0.057) compared to medical treatment (MT). Coronary-artery bypass grafting (CABG) had an overall trend for poorer outcomes: cardiovascular death 2.53 (0.42–15.10), combined cardiovascular death, nonfatal MI, and stroke 2.15 (0.73–6.31) and these events plus late revascularization (2.17, 0.86–5.49). The corresponding numbers for PCI were 0.27 (0.05–1.43) for cardiovascular death, 0.77 (0.32–1.84) for combined cardiovascular death, nonfatal MI, and stroke and 2.35 (1.16–4.77) with the addition of late revascularization. These trends were not influenced by baseline blood pressure, left ventricular ejection fraction and previous MI. Patients with diabetes mellitus had a significantly higher risk of recurrent revascularization when submitted to PCI than CABG. Conclusion: Patients with confirmed CAD in elective coronary angiography do not have a better prognosis when submitted to CABG comparatively to medical treatment. Patients treated with PCI had a trend for the lower incidence of combined cardiovascular events, at the expense of additional revascularization procedures. Patients without significant CAD had a similar prognosis than CAD patients treated with medical therapy

Fractional div-curl quantities and applications to nonlocal geometric equations

We investigate a fractional notion of gradient and divergence operator. We generalize the div-curl estimate by Coifman-Lions-Meyer-Semmes to fractional div-curl quantities, obtaining, in particular, a nonlocal version of Wente's lemma. We demonstrate how these quantities appear naturally in nonlocal geometric equations, which can be used to obtain a theory for fractional harmonic maps analogous to the local theory. Firstly, regarding fractional harmonic maps into spheres, we obtain a conservation law analogous to Shatah's conservation law and give a new regularity proof analogous to H\'elein's for harmonic maps into spheres. Secondly, we prove regularity for solutions to critical systems with nonlocal antisymmetric potentials on the right-hand side. Since the half-harmonic map equation into general target manifolds has this form, as a corollary, we obtain a new proof of the regularity of half-harmonic maps into general target manifolds following closely Rivi\`{e}re's celebrated argument in the local case. Lastly, the fractional div-curl quantities provide also a new, simpler, proof for H\"older continuity of $W^{s,n/s}$-harmonic maps into spheres and we extend this to an argument for $W^{s,n/s}$-harmonic maps into homogeneous targets. This is an analogue of Strzelecki's and Toro-Wang's proof for $n$-harmonic maps into spheres and homogeneous target manifolds, respectively

Necessary and sufficient conditions of solution uniqueness in ℓ1\ell_1 minimization

This paper shows that the solutions to various convex $\ell_1$ minimization problems are \emph{unique} if and only if a common set of conditions are satisfied. This result applies broadly to the basis pursuit model, basis pursuit denoising model, Lasso model, as well as other $\ell_1$ models that either minimize $f(Ax-b)$ or impose the constraint $f(Ax-b)\leq\sigma$, where $f$ is a strictly convex function. For these models, this paper proves that, given a solution $x^*$ and defining I=\supp(x^*) and s=\sign(x^*_I), $x^*$ is the unique solution if and only if $A_I$ has full column rank and there exists $y$ such that $A_I^Ty=s$ and $|a_i^Ty|_\infty<1$ for $i\not\in I$. This condition is previously known to be sufficient for the basis pursuit model to have a unique solution supported on $I$. Indeed, it is also necessary, and applies to a variety of other $\ell_1$ models. The paper also discusses ways to recognize unique solutions and verify the uniqueness conditions numerically.Comment: 6 pages; revised version; submitte

I-mode studies at ASDEX Upgrade: L-I and I-H transitions, pedestal and confinement properties

The I-mode is a plasma regime obtained when the usual L-H power threshold is high, e.g. with unfavourable ion B ∇ direction. It is characterised by the development of a temperature pedestal while the density remains roughly as in the L-mode. This leads to a confinement improvement above the L-mode level which can sometimes reach H-mode values. This regime, already obtained in the ASDEX Upgrade tokamak about two decades ago, has been studied again since 2009 taking advantage of the development of new diagnostics and heating possibilities. The I-mode in ASDEX Upgrade has been achieved with different heating methods such as NBI, ECRH and ICRF. The I-mode properties, power threshold, pedestal characteristics and confinement, are independent of the heating method. The power required at the L-I transition exhibits an offset linear density dependence but, in contrast to the L-H threshold, depends weakly on the magnetic field. The L-I transition seems to be mainly determined by the edge pressure gradient and the comparison between ECRH and NBI induced L-I transitions suggests that the ion channel plays a key role. The I-mode often evolves gradually over a few confinement times until the transition to H-mode which offers a very interesting situation to study the transport reduction and its link with the pedestal formation. Exploratory discharges in which n = 2 magnetic perturbations have been applied indicate that these can lead to an increase of the I-mode power threshold by flattening the edge pressure at fixed heating input power: more heating power is necessary to restore the required edge pressure gradient. Finally, the confinement properties of the I-mode are discussed in detail.European Commission (EUROfusion 633053

Revisiting consistency conditions for quantum states of systems on closed timelike curves: an epistemic perspective

There has been considerable recent interest in the consequences of closed timelike curves (CTCs) for the dynamics of quantum mechanical systems. A vast majority of research into this area makes use of the dynamical equations developed by Deutsch, which were developed from a consistency condition that assumes that mixed quantum states uniquely describe the physical state of a system. We criticise this choice of consistency condition from an epistemic perspective, i.e., a perspective in which the quantum state represents a state of knowledge about a system. We demonstrate that directly applying Deutsch's condition when mixed states are treated as representing an observer's knowledge of a system can conceal time travel paradoxes from the observer, rather than resolving them. To shed further light on the appropriate dynamics for quantum systems traversing CTCs, we make use of a toy epistemic theory with a strictly classical ontology due to Spekkens and show that, in contrast to the results of Deutsch, many of the traditional paradoxical effects of time travel are present.Comment: 10 pages, 6 figures, comments welcome; v2 added references and clarified some points; v3 published versio

Isometric handgrip exercise impacts only on very short-term blood pressure variability, but not on short-term blood pressure variability in hypertensive individuals : a randomized controlled trial

Background: The effect of a single isometric handgrip exercise (IHG) on blood pressure (BP) variability (BPV) has not been addressed. This randomized controlled trial evaluated the effect of IHG vs. sham on BPV and BP. Methods: Hypertensive patients using up to two BP-lowering medications were randomly assigned to IHG (4 × 2 min; 30% of maximal voluntary contraction, MVC, with 1 min rest between sets, unilateral) or sham (protocol; 0.3% of MVC). Systolic and diastolic BP were assessed beat-to-beat in the laboratory before, during, and post-intervention and also using 24-h ambulatory BP monitoring (ABPM). BPV was expressed as average real variability (ARV) and standard deviation (SD). Results: Laboratory BPV, ARV and SD variability, had marked increase during the intervention, but not in the sham group, decreasing in the post-intervention recovery period. The overall change in ARV from pre- to 15 min post-intervention were 0.27 ± 0.07 (IHG) vs. 0.05 ± 0.15 (sham group), with a statistically significant p-value for interaction. Similarly, mean systolic BP increased during the intervention (IHG 165.4 ± 4.5 vs. sham 152.4 ± 3.5 mmHg; p = 0.02) as did diastolic BP (104.0 ± 2.5 vs. 90.5 ± 1.7 mmHg, respectively; p < 0.001) and decreased afterward. However, neither the short-term BPV nor BP assessed by ABPM reached statistically significant differences between groups. Conclusion: A single session of IHG reduces very short-term variability but does not affect short-term variability. IHG promotes PEH in the laboratory, but does not sustain 24-h systolic and diastolic PEH beyond the recovery period