3,495 research outputs found

    Dynamics of a Bose-Einstein Condensate of Excited Magnons

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    The emergence of a non-equilibrium Bose-Einstein-like condensation of magnons in rf-pumped magnetic thin films has recently been experimentally observed. We present here a complete theoretical description of the non-equilibrium processes involved. It it demonstrated that the phenomenon is another example of the presence of a Bose-Einstein-like condensation in non-equilibrium many-boson systems embedded in a thermal bath, better referred-to as Fr\"{o}hlich-Bose-Einstein condensation. The complex behavior emerges after a threshold of the exciting intensity is attained. It is inhibited at higher intensities when the magnon-magnon interaction drives the magnons to internal thermalization. The observed behavior of the relaxation to equilibrium after the end of the pumping pulse is also accounted for and the different processes fully described.Comment: 42 pages, 11 figure

    Wave energy harvesting in the Mediterranean Sea

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    From leeches to personalized medicine: Evolving concepts in the management of polycythemia vera

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    Polycythemia vera is a clonal disorder of hematopoietic stem/progenitor cells. It manifests as an expansion of red cell mass. It is the most common chronic myeloproliferative neoplasm. In virtually all cases, it is characterized by a V617F point mutation in JAK2 exon 14 or less common mutations in exon 12. The landmark discovery of the autonomously activated JAK/STAT signaling pathway paved the way for the clinical development of the first target drug, the JAK1 and JAK2 inhibitor ruxolitinib. This is now approved for patients with resistance or intolerance to hydroxyurea. Phlebotomies and hydroxyurea are still the cornerstone of treatment, and aim to prevent the first appearance or recurrence of cardiovascular events that, together with progression to post-polycythemia vera myelofibrosis and leukemia, represent the main causes of death. Interferon-α is an alternative drug and has been shown to induce molecular remissions. It is currently undergoing phase III trials that might eventually lead to its approval for clinical use. The last few years have witnessed important advances towards an accurate early diagnosis of polycythemia vera, greater understanding of its pathogenesis, and improved patient management. This review will focus on the most recent achievements and will aim to unify the different concepts involved in a personalized approach to the patient with polycythemia vera. In spite of many recent advances in the understanding of its pathogenesis and improved disease management, polycythemia vera remains a life-threatening myeloproliferative neoplasm for which there is no cure. This review will present a critical overview of evolving concepts in diagnosis and treatment of this disease

    Damage to Masonry Structures in the Historic Center of Arezzo (Tuscany, Italy) Following the Excavation of a Sewer Tunnel

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    The work carried out in the 1983-84 period for the building of a sewer line at a shallow depth in the historic center of Arezzo (Tuscany - Italy) caused serious damage to many of the masonry structures. For a depth of 6-7 m., the foundation underground is made of a thick deposit of eterogeneous soils, mainly clayey silt of medium or soft consistency, including elements of gravel, boulders and organic sediment. The tunnel has a circular section, its external diameter being 1.90 m, cover 3.40 - 5.20 m, and the work was carried out using a shield. The method of excavation and the subsequent operation of the tunnel brought about a prolonged disturbance and resettling of the ground in contact with the casing and thus, where fairly large boulders came into contact with the outside edge, gaps formed which were not injected with plastic concrete. On the basis of the geotechnical data available, the surface subsidence has subsequently been calculated and has been compared with what is allowable without damaging the overhead structures

    Discussion and suggestions on design code provisions for seismic stability analyses of artificial slopes

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