417 research outputs found

    Antiproton-deuteron annihilation at low energies

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    Recent experimental studies of the antiproton-deuteron system at low energies have shown that the imaginary part of the antiproton-deuteron scattering length is smaller than the antiproton-proton one. Two- and three-body systems with strong annihilation are investigated and a mechanism explaining this unexpected relation between the imaginary parts of the scattering lengths is proposed.Comment: 6 pages, 3 figures, to be published in The European Physical Journal

    A proteomics approach to the study of bleomycin- induced lung fibrosis

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    Idiopathic pulmonary fibrosis (IPF) is the most severe lung fibrotic form and very few pharmacological therapies are available at present. Key events in the onset of the disease are the activation of fibroblasts to myofibroblasts and the production and release of extracellular matrix (ECM) and molecular factors. Primary murine lung fibroblasts were isolated and their activation induced by Bleomycin (BLM) treatment. Extracellular Vesicles (EV) were isolated and protein extracted. Released soluble proteins (Secretome) and EV-derived proteins were reduced, alkylated and trypsin digested. A nano-LC-MS/MS SWATHTM approach was used for the proteomics analyses. Specific proteins with a putative role in the transition from physiological to fibrotic conditions, such as several matrix metalloproteinases (MMPs), osteopontin (OPN), chitinase-3-like protein1 (CHI3L1) and CD44 resulted differentially released from BLM-treated fibroblasts as compared with untreated lung fibroblasts. Our results provide further understanding of the pathophysiological features of lung fibrosis, and suggest specific target for pharmacological treatments

    Transfusion-Associated Babesiosis after Heart Transplant

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    We describe a 54-year-old spleen-intact man with transfusion-associated Babesia microti infection after a heart transplant. Adult respiratory distress syndrome developed in the patient, and he required mechanical ventilation. Our experiences with this patient suggest that babesiosis should be considered in the differential diagnosis of transplant patients who have fever and hemolytic anemia

    Full coherent control of nuclear spins in an optically pumped single quantum dot

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    Highly polarized nuclear spins within a semiconductor quantum dot (QD) induce effective magnetic (Overhauser) fields of up to several Tesla acting on the electron spin or up to a few hundred mT for the hole spin. Recently this has been recognized as a resource for intrinsic control of QD-based spin quantum bits. However, only static long-lived Overhauser fields could be used. Here we demonstrate fast redirection on the microsecond time-scale of Overhauser fields of the order of 0.5 T experienced by a single electron spin in an optically pumped GaAs quantum dot. This has been achieved using full coherent control of an ensemble of 10^3-10^4 optically polarized nuclear spins by sequences of short radio-frequency (rf) pulses. These results open the way to a new class of experiments using rf techniques to achieve highly-correlated nuclear spins in quantum dots, such as adiabatic demagnetization in the rotating frame leading to sub-micro K nuclear spin temperatures, rapid adiabatic passage, and spin squeezing

    Fluid observers and tilting cosmology

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    We study perfect fluid cosmological models with a constant equation of state parameter Îł\gamma in which there are two naturally defined time-like congruences, a geometrically defined geodesic congruence and a non-geodesic fluid congruence. We establish an appropriate set of boost formulae relating the physical variables, and consequently the observed quantities, in the two frames. We study expanding spatially homogeneous tilted perfect fluid models, with an emphasis on future evolution with extreme tilt. We show that for ultra-radiative equations of state (i.e., Îł>4/3\gamma>4/3), generically the tilt becomes extreme at late times and the fluid observers will reach infinite expansion within a finite proper time and experience a singularity similar to that of the big rip. In addition, we show that for sub-radiative equations of state (i.e., Îł<4/3\gamma < 4/3), the tilt can become extreme at late times and give rise to an effective quintessential equation of state. To establish the connection with phantom cosmology and quintessence, we calculate the effective equation of state in the models under consideration and we determine the future asymptotic behaviour of the tilting models in the fluid frame variables using the boost formulae. We also discuss spatially inhomogeneous models and tilting spatially homogeneous models with a cosmological constant

    Quantum flutter of supersonic particles in one-dimensional quantum liquids

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    The non-equilibrium dynamics of strongly correlated many-body systems exhibits some of the most puzzling phenomena and challenging problems in condensed matter physics. Here we report on essentially exact results on the time evolution of an impurity injected at a finite velocity into a one-dimensional quantum liquid. We provide the first quantitative study of the formation of the correlation hole around a particle in a strongly coupled many-body quantum system, and find that the resulting correlated state does not come to a complete stop but reaches a steady state which propagates at a finite velocity. We also uncover a novel physical phenomenon when the impurity is injected at supersonic velocities: the correlation hole undergoes long-lived coherent oscillations around the impurity, an effect we call quantum flutter. We provide a detailed understanding and an intuitive physical picture of these intriguing discoveries, and propose an experimental setup where this physics can be realized and probed directly.Comment: 13 pages, 9 figure
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