1,115 research outputs found

    Classification of cryptocurrency coins and tokens by the dynamics of their market capitalisations

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    We empirically verify that the market capitalisations of coins and tokens in the cryptocurrency universe follow power-law distributions with significantly different values, with the tail exponent falling between 0.5 and 0.7 for coins, and between 1.0 and 1.3 for tokens. We provide a rationale for this, based on a simple proportional growth with birth & death model previously employed to describe the size distribution of firms, cities, webpages, etc. We empirically validate the model and its main predictions, in terms of proportional growth (Gibrat's law) of the coins and tokens. Estimating the main parameters of the model, the theoretical predictions for the power-law exponents of coin and token distributions are in remarkable agreement with the empirical estimations, given the simplicity of the model. Our results clearly characterize coins as being "entrenched incumbents" and tokens as an "explosive immature ecosystem", largely due to massive and exuberant Initial Coin Offering activity in the token space. The theory predicts that the exponent for tokens should converge to 1 in the future, reflecting a more reasonable rate of new entrants associated with genuine technological innovations

    Laser thermal ablation to treat a recurrent soft-tissue sarcoma of the leg : A case report

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    We present the case of a 52-year-old male patient with recurrence of a soft-tissue sarcoma of the left leg treated with percutaneous laser ablation. The patient received the diagnosis of sarcoma for the first time in 2011; further local recurrences and a pulmonary metastatic spread occurred during follow-up, so the patient has been treated several times with chemotherapy, limb-sparing surgery and radiotherapy. In September 2017, a new local recurrence of sarcoma occurred, for which limb amputation was proposed but refused by the patient. Laser ablation with ultrasound guidance was performed, with complete ablation at 6 months and limb salvage

    Accuracy of inference on the physics of binary evolution from gravitational-wave observations

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    The properties of the population of merging binary black holes encode some of the uncertain physics of the evolution of massive stars in binaries. The binary black hole merger rate and chirp mass distribution are being measured by ground-based gravitational-wave detectors. We consider isolated binary evolution and explore how accurately the physical model can be constrained with such observations by applying the Fisher information matrix to the merging black hole population simulated with the rapid binary population synthesis code COMPAS. We investigate variations in four COMPAS parameters: common envelope efficiency, kick velocity dispersion, and mass loss rates during the luminous blue variable and Wolf--Rayet stellar evolutionary phases. We find that 1000 observations would constrain these model parameters to a fractional accuracy of a few percent. Given the empirically determined binary black hole merger rate, we can expect gravitational-wave observations alone to place strong constraints on the physics of stellar and binary evolution within a few years.Comment: 12 pages, 9 figures; version accepted by Monthly Notices of the Royal Astronomical Societ

    Estimativas da diversidade genética de acessos de Paspalum spp. com ouso de marcadores microssatélites.

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    Editores técnicos: João de Mendonça Naime, Caue Ribeiro, Maria Alice Martins, Elaine Cristina Paris, Paulino Ribeiro Villas Boas, Ladislau Marcelino Rabello

    Targeting the MET oncogene by concomitant inhibition of receptor and ligand via an antibody-“decoy” strategy

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    MET, a master gene sustaining "invasive growth," is a relevant target for cancer precision therapy. In the vast majority of tumors, wild-type MET behaves as a "stress-response" gene and relies on the ligand (HGF) to sustain cell "scattering," invasive growth and apoptosis protection (oncogene "expedience"). In this context, concomitant targeting of MET and HGF could be crucial to reach effective inhibition. To test this hypothesis, we combined an anti-MET antibody (MvDN30) inducing "shedding" (i.e., removal of MET from the cell surface), with a "decoy" (i.e., the soluble extracellular domain of the MET receptor) endowed with HGF-sequestering ability. To avoid antibody/decoy interaction-and subsequent neutralization-we identified a single aminoacid in the extracellular domain of MET-lysine 842-that is critical for MvDN30 binding and engineered the corresponding recombinant decoyMET (K842E). DecoyMET(K842E) retains the ability to bind HGF with high affinity and inhibits HGF-induced MET phosphorylation. In HGF-dependent cellular models, MvDN30 antibody and decoyMET(K842E) used in combination cooperate in restraining invasive growth, and synergize in blocking cancer cell "scattering." The antibody and the decoy unbridle apoptosis of colon cancer stem cells grown in vitro as spheroids. In a preclinical model, built by orthotopic transplantation of a human pancreatic carcinoma in SCID mice engineered to express human HGF, concomitant treatment with antibody and decoy significantly reduces metastatic spread. The data reported indicate that vertical targeting of the MET/HGF axis results in powerful inhibition of ligand-dependent MET activation, providing proof of concept in favor of combined target therapy of MET "expedience.

    Évolutions rĂ©centes de la productivitĂ© : accĂ©lĂ©ration structurelle dans la zone euro et ralentissement structurel aux États-Unis ?

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    La croissance de la productivitĂ© dans la zone euro et aux États-Unis a connu sur la pĂ©riode rĂ©cente des inflexions significatives, respectivement Ă  la hausse et Ă  la baisse, qui sembleraient relever en partie d’évolutions structurelles.ProductivitĂ©, technologies de l’information et de la communication (TIC), dynamique sectorielle, Ă©volutions structurelles.

    La situation financiĂšre des sociĂ©tĂ©s non financiĂšres en France 1995-2006. Baisse du taux d’épargne et recours accru Ă  l’endettement.

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    Comme le montrent les statistiques de comptabilitĂ© nationale et les comptes d’entreprise, le taux de marge et la rentabilitĂ© Ă©conomique des entreprises ayant stagnĂ©, la hausse des dividendes et des impĂŽts pĂšse sur le taux d’épargne. L’investissement, spĂ©cialement dynamique dans le secteur immobilier, est donc financĂ© par un surcroĂźt d’endettement.ComptabilitĂ© nationale, comptabilitĂ© d’entreprise, endettement, Ă©pargne, rentabilitĂ©.
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