581 research outputs found

    Comment on "Acoustics of tachyon Fermi gas" [E. Trojan and G.V. Vlasov, arXiv:1103.2276 (hep-ph)]

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    In contrast to Trojan and Vlasov [arXiv:1103.2276 (hep-ph)], it is found that an ideal Fermi gas of tachyons has a subluminous velocity of sound for any particle density and, therefore, the causality condition for a tachyon gas holds always true. Also, an ideal Fermi gas of tachyons never possesses an exotic equation of state with the pressure exceeding the energy density.Comment: 1 page + Ref

    Shock waves in superconducting cosmic strings: growth of current

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    Intrinsic equations of motion of superconducting cosmic string may admit solutions in the shock-wave form that implies discontinuity of the current term \chi. The hypersurface of discontinuity propagates at finite velocity determined by finite increment \Delta \chi =\chi_+ -\chi_-. The current increases \chi_+>\chi_- in stable shocks but transition between spacelike (\chi >0) and timelike (\chi<0) currents is impossible.Comment: 13 pages, 3 figure

    Evaluation of selected characteristics in industrial hemp after phytohormonal treatment

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    Plant growth and development is significantly influenced by phytohormones \u2013 endogenous molecules present naturally in plants. The best known plant hormones are auxins and cytokinins. This study examined the possible effect of externally applied plant hormone analogues (growth regulators): 1-naphthyl acetic acid (NAA) and 6-benzyl aminopurine (BAP) on industrial fibre hemp (Cannabis sativa L., variety Bialobrzeskie). Plants were treated with three different concentrations of NAA (5, 10 and 20 mg/l) and three different concentrations of BAP (10, 25 and 50 mg/l). Morphological and physiological characteristics, such as apical dominance, shoot branching, fibre properties, and flavonoid content were evaluated. The chosen variety of hemp had a significant response to exogenous application of growth regulators, as has been observed with other plant species. Most notably completely understood and controlled synthetic auxin treatment has a potential to increase the bark fibre yield of hemp

    Tumor and circulating biomarkers in patients with second-line hepatocellular carcinoma from the randomized phase II study with tivantinib

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    ARQ 197-215 was a randomized placebo-controlled phase II study testing the MET inhibitor tivantinib in second-line hepatocellular carcinoma (HCC) patients. It identified tumor MET as a key biomarker in HCC. Aim of this research was to study the prognostic and predictive value of tumor (MET, the receptor tyrosine kinase encoded by the homonymous MNNG-HOS transforming gene) and circulating (MET, hepatocyte growth factor [HGF], alpha-fetoprotein [AFP], vascular endothelial growth factor [VEGF]) biomarkers in second-line HCC. Tumor MET-High status was centrally assessed by immunohistochemistry. Circulating biomarkers were centrally analyzed on serum samples collected at baseline and every 4-8 weeks, using medians as cut-off to determine High/Low status. Tumor MET, tested in 77 patients, was more frequently High after (82%) versus before (40%) sorafenib. A significant interaction (p = 0.04) between tivantinib and baseline tumor MET in terms of survival was observed. Baseline circulating MET and HGF (102 patients) High status correlated with shorter survival (HR 0.61, p = 0.03, and HR 0.60, p = 0.02, respectively), while the association between AFP (104 patients) or VEGF (103 patients) status and survival was non-significant. Conclusions: Tumor MET levels were higher in patients treated with sorafenib. Circulating biomarkers such as MET and HGF may be prognostic in second-line HCC. These results need to be confirmed in larger randomized clinical trials

    Expressive and Instrumental Offending: Reconciling the Paradox of Specialisation and Versatility

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    Although previous research into specialisation has been dominated by the debate over the existence of specialisation versus versatility, it is suggested that research needs to move beyond the restrictions of this dispute. The current study explores the criminal careers of 200 offenders based on their criminal records, obtained from a police database in the North West of England, aiming to understand the patterns and nature of specialisation by determining the presence of differentiation within their general offending behaviours and examining whether the framework of Expressive and Instrumental offending styles can account for any specialised tendencies that emerge. Fifty-eight offences were subjected to Smallest Space Analysis. Results revealed that a model of criminal differentiation could be identified and that any specialisation is represented in terms of Expressive and Instrumental offending styles

    Transparent dense sodium

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    Under pressure, metals exhibit increasingly shorter interatomic distances. Intuitively, this response is expected to be accompanied by an increase in the widths of the valence and conduction bands and hence a more pronounced free-electron-like behaviour. But at the densities that can now be achieved experimentally, compression can be so substantial that core electrons overlap. This effect dramatically alters electronic properties from those typically associated with simple free-electron metals such as lithium and sodium, leading in turn to structurally complex phases and superconductivity with a high critical temperature. But the most intriguing prediction - that the seemingly simple metals Li and Na will transform under pressure into insulating states, owing to pairing of alkali atoms - has yet to be experimentally confirmed. Here we report experimental observations of a pressure-induced transformation of Na into an optically transparent phase at 200 GPa (corresponding to 5.0-fold compression). Experimental and computational data identify the new phase as a wide bandgap dielectric with a six-coordinated, highly distorted double-hexagonal close-packed structure. We attribute the emergence of this dense insulating state not to atom pairing, but to p-d hybridizations of valence electrons and their repulsion by core electrons into the lattice interstices. We expect that such insulating states may also form in other elements and compounds when compression is sufficiently strong that atomic cores start to overlap strongly.Comment: Published in Nature 458, 182-185 (2009

    Droits de l'homme et libertés fondamentales - Droit de propriété

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    Multiple myeloma (MM) is a B cell bone marrow neoplasia characterized by inflammation with an intense secretion of growth factors that promote tumor growth, cell survival, migration and invasion. The aim of this study was to evaluate the effects of pravastatin, a drug used to reduce cholesterol, in a MM cell line.Cell cycle and viability were determinate by Trypan Blue and Propidium Iodide. IL6, VEGF, bFGF and TGFβ were quantified by ELISA and qRT-PCR including here de HMG CoA reductase. It was observed reduction of cell viability, increase of cells in G0/G1 phase of the cell cycle and reducing the factors VEGF and bFGF without influence on 3-Methyl-Glutaryl Coenzyme A reductase expression.The results demonstrated that pravastatin induces cell cycle arrest in G0/G1 and decreased production of growth factors in Multiple Myeloma cell line
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