1,565 research outputs found

    Theoretical study of charge exchange dynamics in He+^+ + NO collisions

    Full text link
    We investigate the charge transfer mechanism in the collisions of helium ions on nitric oxide using a molecular description framework with consideration of the orientation of the projectile toward the target. The anisotropy of the collision process has been analysed in detail in connection with the non-adiabatic interactions around avoided crossings. Potential energy curves, radial and rotational coupling matrix elements have been determined by means of ab initio quantum chemical methods. The collision dynamics is performed in the [1.-25.] keV collision energy range using a semiclassical approach, and the total electron transfer cross sections are analysed with regard to available experimental data.Comment: 16 pages, 3 tables, 6 figure

    Thermal entanglement in the nanotubular system Na_2V_3O_7

    Full text link
    Macroscopic entanglement witnesses have been put forward recently to reveal nonlocal quantum correlations between individual constituents of the solid at nonzero temperatures. Here we apply a recently proposed universal entanglement witness, the magnetic susceptibility [New J. Phys. {\bf 7}, 258 (2005)] for the estimation of the critical temperature TcT_c in the nanotubular system Na2V3O7{\rm Na_2V_3O_7} below which thermal entanglement is present. As a result of an analysis based on the experimental data for dc-magnetic susceptibility, we show that Tc365T_c \approx 365 K, which is approximately three times higher than the critical temperature corresponding to the bipartite entanglement.Comment: 6 pages, 3 figures, REVTeX

    Polyphenol Contents of Skin-Contact Fermented White Wines

    Get PDF
    Skin-contact fermented white wines, the so-called orange or qvevri wines, have been gaining international attention from winemakers, importers, sommeliers, consumers, and journalists over the last 10 years. Sommeliers are now regularly pairing orange wines with fine cuisine. This new culinary trend is part of a general move by the consumer wishing to respect the existence of traditions and innovation, combined with a growing interest in environmental awareness and healthy options. Orange wines are made from white grapes using ancient Georgian techniques. The essence of this method is the long skin-contact fermentation in amphorae without any chemicals or specific yeast. In our work, the polyphenol content of orange wines, in particular total polyphenol and catechin content, as well as colour intensity were measured to ensure safe winemaking technology without oxidized components

    The Kohn mode for trapped Bose gases within the dielectric formalism

    Get PDF
    The presence of undamped harmonic center of mass oscillations of a weakly interacting Bose gas in a harmonic trap is demonstrated within the dielectric formalism for a previously introduced finite temperature approximation including exchange. The consistency of the approximation with the Kohn theorem is thereby demonstrated. The Kohn modes are found explicitly, generalizing an earlier zero-temperature result found in the literature. It is shown how the Kohn mode disappears from the single-particle spectrum, while remaining in the density oscillation spectrum, when the temperature increases from below to above the condensation temperature.Comment: 6 pages revte

    Standing naked in the storm– European citizens’ trust in social media, users, information

    Get PDF
    We have surveyed users in 7 European countries about the factors that underwrite their trust in and on Facebook. We identified three trust pillars: (1) self-confidence to recognize and hedge platform related risks; (2) trust in the platform’s ability and willingness to protect users against online harms; and (3) national and European platform regulation, and measured their role in shaping users' trusting attitudes towards the platform and the users and information they encounter on the platform.Our finding suggests serious deficiencies in how trust in such a critical societal infrastructure is structured. First, we found that trust in and on the platform is mostly defined by generic, rather than platform-specific trust attitudes and expectations. Second, our data suggests that the two most important platform-specific trust pillars are rather shaky. On the one hand, users trust the platform to protect them, while there is ample evidence of Facebook and its parent company, Meta to not act in the best interest of their users. On the other hand, users base their trust on their perceived ability to protect themselves, while our data shows that they do not seem to use the even the very limited set of tools the platform provides them for such self-protection.Lastly, while governments seem to be best positioned to reign in global digital service providers, and in recent years the EU spent enormous amounts of resources to regulate online platforms, users don’t seem to expect regulation to make platforms and the information herein trustworthy. Such lack of expectations towards the only agents in this ecosystem who can provide any effective trustworthiness safeguards vis-à-vis platforms is somewhat disturbing

    Phase diagram of the random field Ising model on the Bethe lattice

    Get PDF
    The phase diagram of the random field Ising model on the Bethe lattice with a symmetric dichotomous random field is closely investigated with respect to the transition between the ferromagnetic and paramagnetic regime. Refining arguments of Bleher, Ruiz and Zagrebnov [J. Stat. Phys. 93, 33 (1998)] an exact upper bound for the existence of a unique paramagnetic phase is found which considerably improves the earlier results. Several numerical estimates of transition lines between a ferromagnetic and a paramagnetic regime are presented. The obtained results do not coincide with a lower bound for the onset of ferromagnetism proposed by Bruinsma [Phys. Rev. B 30, 289 (1984)]. If the latter one proves correct this would hint to a region of coexistence of stable ferromagnetic phases and a stable paramagnetic phase.Comment: Article has been condensed and reorganized; Figs 3,5,6 merged; Fig 4 omitted; Some discussion added at end of Sec. III; 9 pages, 5 figs, RevTeX4, AMSTe

    A two-qubit Bell inequality for which POVM measurements are relevant

    Full text link
    A bipartite Bell inequality is derived which is maximally violated on the two-qubit state space if measurements describable by positive operator valued measure (POVM) elements are allowed rather than restricting the possible measurements to projective ones. In particular, the presented Bell inequality requires POVMs in order to be maximally violated by a maximally entangled two-qubit state. This answers a question raised by N. Gisin.Comment: 7 pages, 1 figur

    Stationary Properties of a Randomly Driven Ising Ferromagnet

    Full text link
    We consider the behavior of an Ising ferromagnet obeying the Glauber dynamics under the influence of a fast switching, random external field. Analytic results for the stationary state are presented in mean-field approximation, exhibiting a novel type of first order phase transition related to dynamic freezing. Monte Carlo simulations performed on a quadratic lattice indicate that many features of the mean field theory may survive the presence of fluctuations.Comment: 5 pages in RevTex format, 7 eps/ps figures, send comments to "mailto:[email protected]", submitted to PR

    Monitoring PD-L1 positive circulating tumor cells in non-small cell lung cancer patients treated with the PD-1 inhibitor Nivolumab

    Get PDF
    Controversial results on the predictive value of programmed death ligand 1 (PD-L1) status in lung tumor tissue for response to immune checkpoint inhibitors do not allow for any conclusive consideration. Liquid biopsy might allow real-time sampling of patients for PD-L1 through the course of the disease. Twenty-four stage IV NSCLC patients included in the Expanded Access Program with Nivolumab were enrolled. Circulating tumor cells (CTCs) were analyzed by CellSearch with anti-human B7-H1/PD-L1 PE-conjugated antibody. PD-L1 expressing CTCs were assessed at baseline, at 3 and 6 months after starting therapy, and correlated with outcome. At baseline and at 3 months of treatment, the presence of CTCs and the expression of PD-L1 on their surface were found associated to poor patients outcome. Nevertheless, the high frequency of PD-L1 expressing CTCs hampered to discriminate the role of PD-L1 in defining prognosis. Conversely although CTCs were found in all patients 6 months after treatment, at this time patients could be dichotomized into two groups based PD-L1 expression on CTCs. Patients with PD-L1 negative CTCs all obtained a clinical benefit, while patients with PD-L1 (+) CTCs all experienced progressive disease. This suggests that the persistence of PD-L1(+) CTCs might mirror a mechanism of therapy escape
    corecore