1,649 research outputs found

    Thymomas: a review.

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    Thymomas are neoplasma of thymic epithelial cells. They may be benign or malignant and may associate with locai ìnvasiveness and paraneoplastic diseases. Myasthenia gravis is often associated with thymomas, bui this is not thè rule. Several classifications have been proposed: some of them follow thè histopathological findings (Rosai and Levine, Snover, Marino and Muller- Hermelink classification), other emphasizes thè clinic-pathological stage (Masaoka, Verley and Hollmann stadiation). One third of thymomas is asymptomatic. Diagnosis is made often by plain X-ray and confirmed by Computed Tomography or fine needle biopsy. Surgery is effective in 100% of noninvasive cases and in 58% of invasive ones. Radio and chemotherapy are recommended only in advanced or inoperable stages

    Metastability, negative specific heat and weak mixing in classical long-range many-rotator system

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    We perform a molecular dynamical study of the isolated d=1d=1 classical Hamiltonian H=1/2i=1NLi2+ij1cos(θiθj)rijα;(α0){\cal H} = {1/2} \sum_{i=1}^N L_i^2 + \sum_{i \ne j} \frac{1-cos(\theta_i-\theta_j)}{r_{ij}^\alpha} ;(\alpha \ge 0), known to exhibit a second order phase transition, being disordered for uU/NN~uc(α,d)u \equiv U/N{\tilde N} \ge u_c(\alpha,d) and ordered otherwise (UU\equiv total energy and N~N1α/dα/d1α/d{\tilde N} \equiv \frac{N^{1-\alpha/d}-\alpha/d}{1-\alpha/d}). We focus on the nonextensive case α/d1\alpha/d \le 1 and observe that, for u<ucu<u_c, a basin of attraction exists for the initial conditions for which the system quickly relaxes onto a longstanding metastable state (whose duration presumably diverges with NN like N~{\tilde N}) which eventually crosses over to the microcanonical Boltzmann-Gibbs stable state. The temperature associated with the (scaled) average kinetic energy per particle is lower in the metastable state than in the stable one. It is exhibited for the first time that the appropriately scaled maximal Lyapunov exponent λu<ucmax(metastable)Nκmetastable;(N)\lambda_{u<u_c}^{max}(metastable) \propto N^{-\kappa_{metastable}} ;(N \to \infty), where, for all values of α/d\alpha/d, κmetastable\kappa_{metastable} numerically coincides with {\it one third} of its value for u>ucu>u_c, hence decreases from 1/9 to zero when α/d\alpha/d increases from zero to unity, remaining zero thereafter. This new and simple {\it connection between anomalies above and below the critical point} reinforces the nonextensive universality scenario.Comment: 9 pages and 4 PS figure

    Cost-utility and biological underpinnings of Mindfulness-Based Stress Reduction (MBSR) versus a psychoeducational programme (FibroQoL) for fibromyalgia: a 12-month randomised controlled trial (EUDAIMON study)

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    Background: The EUDAIMON study focuses on fibromyalgia syndrome (FMS), a prevalent chronic condition characterized by pain, fatigue, cognitive problems and distress. According to recent reviews and meta-analyses, Mindfulness-Based Stress Reduction (MBSR) is a promising therapeutic approach for patients with FMS. The measurement of biomarkers as part of the analysis of MBSR effects would help to identify the neurobiological underpinnings of MBSR and increase our knowledge of FMS pathophysiology. The main objectives of this 12-month RCT are: firstly, to examine the effectiveness and cost-utility for FMS patients of MBSR as an add-on to treatment as usual (TAU) versus TAU + the psychoeducational programme FibroQoL, and versus TAU only; secondly, to examine pre-post differences in brain structure and function, as well as levels of specific inflammatory markers in the three study arms and; thirdly, to analyse the role of some psychological variables as mediators of 12-month clinical outcomes. Methods: Effectiveness, cost-utility, and neurobiological analyses performed alongside a 12-month RCT. The participants will be 180 adult patients with FMS recruited at the Sant Joan de Déu hospital (St. Boi de Llobregat, Spain), randomly allocated to one of the three study arms: TAU + MBSR vs. TAU + FibroQol vs. TAU. A comprehensive assessment to collect functional, quality of life, distress, costs, and psychological variables will be conducted pre-, post-intervention, and at 12-month post-intervention. Fifty per cent of study participants will be evaluated at pre- and post-treatment using Voxel-Based Morphometry, Diffusion Tensor Imaging, pseudo-continuous Arterial Spin Labeling, and resting state fMRI. A cytokine multiplex kit of high-sensitivity will be applied (cytokines IL-6, IL-8, IL-10 + high-sensitivity CRP test). Discussion: The findings obtained from this RCT will indicate whether MBSR is potentially cost-effective for FMS and contribute to knowledge of any brain and inflammatory changes associated with MBSR in FMS patients. Specifically, we will determine whether there are morphometric and functional changes associated with participation in MBSR in brain regions related to meta-awareness, body awareness, memory consolidation-reconsolidation, emotion regulation and in networks postulated to underpin the sensory-discriminative, cognitive-evaluative and affective-motivational aspects of the pain experience. Trial registration: NCT02561416. Registered 23 September 201

    Classification of phase transitions and ensemble inequivalence, in systems with long range interactions

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    Systems with long range interactions in general are not additive, which can lead to an inequivalence of the microcanonical and canonical ensembles. The microcanonical ensemble may show richer behavior than the canonical one, including negative specific heats and other non-common behaviors. We propose a classification of microcanonical phase transitions, of their link to canonical ones, and of the possible situations of ensemble inequivalence. We discuss previously observed phase transitions and inequivalence in self-gravitating, two-dimensional fluid dynamics and non-neutral plasmas. We note a number of generic situations that have not yet been observed in such systems.Comment: 42 pages, 11 figures. Accepted in Journal of Statistical Physics. Final versio

    The spectrum of high-energy cosmic rays measured with KASCADE-Grande

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    The energy spectrum of cosmic rays between 10**16 eV and 10**18 eV, derived from measurements of the shower size (total number of charged particles) and the total muon number of extensive air showers by the KASCADE-Grande experiment, is described. The resulting all-particle energy spectrum exhibits strong hints for a hardening of the spectrum at approximately 2x10**16 eV and a significant steepening at c. 8x10**16 eV. These observations challenge the view that the spectrum is a single power law between knee and ankle. Possible scenarios generating such features are discussed in terms of astrophysical processes that may explain the transition region from galactic to extragalactic origin of cosmic rays.Comment: accepted by Astroparticle Physics June 201

    Short-term changes in left and right systolic function following ferric carboxymaltose : a substudy of the Myocardial-IRON trial

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    Funding: This work was supported in part by an unrestricted grant from Vifor Pharma and Proyectos de Investigación de la Sección de Insuficiencia Cardiaca 2017 from Sociedad Española de Cardiología.The mechanisms underlying the beneficial effect of ferric carboxymaltose (FCM) in patients with heart failure (HF) and iron deficiency (ID) have not been completely characterized. The Myocardial-IRON trial was a double-blind, randomized trial that evaluated myocardial iron repletion following FCM vs. placebo in 53 patients with HF and ID. In this post hoc analysis, we evaluated whether treatment with FCM was associated with cardiac magnetic resonance changes in left and right ventricular function (LVEF and RVEF, respectively) at different points of systolic dysfunction. We included patients from the Myocardial-IRON trial with left and right ventricular systolic dysfunction (LVSD and RVSD, respectively) at enrolment. Linear mixed regression models were used to evaluate changes at 7 and 30 days on LVEF and RVEF at cardiac magnetic resonance. At enrolment, 27 (50.9%) and 38 (71.7%) patients had LVEF < 40% (LVSD) or <45% (LVSD), respectively, and 10 (18.9%) and 17 (32.1%) patients had RVEF < 45% (RVSD) or <51% in women and <52% in men (RVSD, respectively. Treatment with FCM was associated with a significant improvement in LVEF at 30 days (LVSD: Δ2.3%, P < 0.001; LVSD: Δ4.1, P = 0.014). FCM was also associated with a significant and early improvement in RVEF at 7 days (RVSD: Δ6.9%, P = 0.003; RVSD: Δ3.2%, P = 0.003) that persisted at 30 days (RVSD: Δ8.1%, P < 0.001; RVSD: Δ4.7%, P < 0.001). In patients with HF and systolic dysfunction with ID, FCM was associated with short-term improvement in LVEF and, especially, in RVEF

    The primary cosmic ray composition between 10**15 and 10**16 eV from Extensive Air Showers electromagnetic and TeV muon data

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    The cosmic ray primary composition in the energy range between 10**15 and 10**16 eV, i.e., around the "knee" of the primary spectrum, has been studied through the combined measurements of the EAS-TOP air shower array (2005 m a.s.l., 10**5 m**2 collecting area) and the MACRO underground detector (963 m a.s.l., 3100 m w.e. of minimum rock overburden, 920 m**2 effective area) at the National Gran Sasso Laboratories. The used observables are the air shower size (Ne) measured by EAS-TOP and the muon number (Nmu) recorded by MACRO. The two detectors are separated on average by 1200 m of rock, and located at a respective zenith angle of about 30 degrees. The energy threshold at the surface for muons reaching the MACRO depth is approximately 1.3 TeV. Such muons are produced in the early stages of the shower development and in a kinematic region quite different from the one relevant for the usual Nmu-Ne studies. The measurement leads to a primary composition becoming heavier at the knee of the primary spectrum, the knee itself resulting from the steepening of the spectrum of a primary light component (p, He). The result confirms the ones reported from the observation of the low energy muons at the surface (typically in the GeV energy range), showing that the conclusions do not depend on the production region kinematics. Thus, the hadronic interaction model used (CORSIKA/QGSJET) provides consistent composition results from data related to secondaries produced in a rapidity region exceeding the central one. Such an evolution of the composition in the knee region supports the "standard" galactic acceleration/propagation models that imply rigidity dependent breaks of the different components, and therefore breaks occurring at lower energies in the spectra of the light nuclei.Comment: Submitted to Astroparticle Physic

    Particle Acceleration in Cosmic Sites - Astrophysics Issues in our Understanding of Cosmic Rays

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    Laboratory experiments to explore plasma conditions and stimulated particle acceleration can illuminate aspects of the cosmic particle acceleration process. Here we discuss the cosmic-ray candidate source object variety, and what has been learned about their particle-acceleration characteristics. We identify open issues as discussed among astrophysicists. -- The cosmic ray differential intensity spectrum is a rather smooth power-law spectrum, with two kinks at the "knee" (~10^15 eV) and at the "ankle" (~3 10^18 eV). It is unclear if these kinks are related to boundaries between different dominating sources, or rather related to characteristics of cosmic-ray propagation. We believe that Galactic sources dominate up to 10^17 eV or even above, and the extragalactic origin of cosmic rays at highest energies merges rather smoothly with Galactic contributions throughout the 10^15--10^18 eV range. Pulsars and supernova remnants are among the prime candidates for Galactic cosmic-ray production, while nuclei of active galaxies are considered best candidates to produce ultrahigh-energy cosmic rays of extragalactic origin. Acceleration processes are related to shocks from violent ejections of matter from energetic sources such as supernova explosions or matter accretion onto black holes. Details of such acceleration are difficult, as relativistic particles modify the structure of the shock, and simple approximations or perturbation calculations are unsatisfactory. This is where laboratory plasma experiments are expected to contribute, to enlighten the non-linear processes which occur under such conditions.Comment: accepted for publication in EPJD, topical issue on Fundamental physics and ultra-high laser fields. From review talk at "Extreme Light Infrastructure" workshop, Sep 2008. Version-2 May 2009: adjust some wordings and references at EPJD proofs stag
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