11,861 research outputs found

    Fuzzy Authentication using Rank Distance

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    Fuzzy authentication allows authentication based on the fuzzy matching of two objects, for example based on the similarity of two strings in the Hamming metric, or on the similiarity of two sets in the set difference metric. Aim of this paper is to show other models and algorithms of secure fuzzy authentication, which can be performed using the rank metric. A few schemes are presented which can then be applied in different scenarios and applications.Comment: to appear in Cryptography and Physical Layer Security, Lecture Notes in Electrical Engineering, Springe

    Phase-field-crystal model for liquid crystals

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    Based on static and dynamical density functional theory, a phase-field-crystal model is derived which involves both the translational density and the orientational degree of ordering as well as a local director field. The model exhibits stable isotropic, nematic, smectic A, columnar, plastic crystalline and orientationally ordered crystalline phases. As far as the dynamics is concerned, the translational density is a conserved order parameter while the orientational ordering is non-conserved. The derived phase-field-crystal model can serve for efficient numerical investigations of various nonequilibrium situations in liquid crystals

    Spectroscopy along flerovium decay chains: Discovery of 280Ds and an excited state in 282Cn

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    ArtĂ­culo escrito por un elevado nĂșmero de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboraciĂłn, si le hubiere, y los autores pertenecientes a la UAMA nuclear spectroscopy experiment was conducted to study α-decay chains stemming from isotopes of flerovium (element Z = 114). An upgraded TASISpec decay station was placed behind the gas-filled separator TASCA at the GSI Helmholtzzentrum fĂŒr Schwerionenforschung in Darmstadt, Germany. The fusion-evaporation reactions 48Ca + 242Pu and 48Ca + 244Pu provided a total of 32 flerovium-candidate decay chains, of which two and eleven were firmly assigned to 286Fl and 288Fl, respectively. A prompt coincidence between a 9.60(1)-MeV α particle event and a 0.36(1)-MeV conversion electron marked the first observation of an excited state in an even-even isotope of the heaviest man-made elements, namely 282Cn. Spectroscopy of 288Fl decay chains fixed Qα = 10.06(1) MeV. In one case, a Qα = 9.46(1)-MeV decay from 284Cn into 280Ds was observed, with 280Ds fissioning after only 518 ÎŒs. The impact of these findings, aggregated with existing data on decay chains of 286,288Fl, on the size of an anticipated shell gap at proton number Z = 114 is discussed in light of predictions from two beyond-mean-field calculations, which take into account triaxial deformatio

    Bethe Ansatz solution of a decagonal rectangle triangle random tiling

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    A random tiling of rectangles and triangles displaying a decagonal phase is solved by Bethe Ansatz. Analogously to the solutions of the dodecagonal square triangle and the octagonal rectangle triangle tiling an exact expression for the maximum of the entropy is found.Comment: 17 pages, 4 figures, some remarks added and typos correcte

    Transport properties of highly asymmetric hard-sphere mixtures

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    The static and dynamic properties of binary mixtures of hard spheres with a diameter ratio of sigma(B)/sigma(A)= 0.1 and a mass ratio of m(B)/m(A)= 0.001 are investigated using event driven molecular dynamics. The contact values of the pair correlation functions are found to compare favorably with recently proposed theoretical expressions. The transport coefficients of the mixture, determined from simulation, are compared to the predictions of the revised Enskog theory using both a third-order Sonine expansion and direct simulation Monte Carlo. Overall, the Enskog theory provides a fairly good description of the simulation data, with the exception of systems at the smallest mole fraction of larger spheres (x(A)=0.01) examined. A "fines effect" was observed at higher packing fractions, where adding smaller spheres to a system of large spheres decreases the viscosity of the mixture; this effect is not captured by the Enskog theory

    Evidence for phase formation in potassium intercalated 1,2;8,9-dibenzopentacene

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    We have prepared potassium intercalated 1,2;8,9-dibenzopentacene films under vacuum conditions. The evolution of the electronic excitation spectra upon potassium addition as measured using electron energy-loss spectroscopy clearly indicate the formation of particular doped phases with compositions Kx_xdibenzopentacene (xx = 1,2,3). Moreover, the stability of these phases as a function of temperature has been explored. Finally, the electronic excitation spectra also give insight into the electronic ground state of the potassium doped 1,2;8,9-dibenzopentacene films.Comment: 6 pages, 5 figures. arXiv admin note: text overlap with arXiv:1201.200

    Theory of asymmetric non-additive binary hard-sphere mixtures

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    We show that the formal procedure of integrating out the degrees of freedom of the small spheres in a binary hard-sphere mixture works equally well for non-additive as it does for additive mixtures. For highly asymmetric mixtures (small size ratios) the resulting effective Hamiltonian of the one-component fluid of big spheres, which consists of an infinite number of many-body interactions, should be accurately approximated by truncating after the term describing the effective pair interaction. Using a density functional treatment developed originally for additive hard-sphere mixtures we determine the zero, one, and two-body contribution to the effective Hamiltonian. We demonstrate that even small degrees of positive or negative non-additivity have significant effect on the shape of the depletion potential. The second virial coefficient B2B_2, corresponding to the effective pair interaction between two big spheres, is found to be a sensitive measure of the effects of non-additivity. The variation of B2B_2 with the density of the small spheres shows significantly different behavior for additive, slightly positive and slightly negative non-additive mixtures. We discuss the possible repercussions of these results for the phase behavior of binary hard-sphere mixtures and suggest that measurements of B2B_2 might provide a means of determining the degree of non-additivity in real colloidal mixtures

    Neoadjuvant radiochemotherapy for locally advanced gastric cancer: a phase I-II study

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    Background: To study in a phase I-II trial the maximum tolerated dose, the toxicity, and the tolerance of adding radiotherapy to systemic chemotherapy administered preoperatively in patients with locoregionally advanced gastric adenocarcinoma. Patients and methods: Patients with adenocarcinoma of the stomach (T3-4Nany or TanyN+), performance status ≀1, normal hematological, hepatic and renal functions received two cycles of cisplatin 100 mg/m2 on day 1, 5-FU 800 mg/m2 on days 1 to 4 and leucovorin 60 mg b.i.d. on days 1 to 4 q3w, concomitantly with radiation therapy escalated in three dose tiers (31.2, 38.4 and 45.6 Gy). Results: Nineteen patients were accrued and 18 completed neoadjuvant therapy. Major toxicity consisted of grade 3/4 leucopenia and mucositis in 89% and 36% of the patients, respectively. Only one episode of febrile neutropenia was recorded. Dose level number 2 (38.4 Gy) with the chemotherapy given q4w is the recommended dose level. All patients were subsequently operated and no fatalities occurred. Pathological assessment showed one complete and eight partial responses. Two- and 3-year relapse-free survival rates were 57% and 50%, respectively. Only one patient relapsed locally. The peritoneum was the most frequent site of relapse. Conclusions: This neoadjuvant therapeutic program is relatively well tolerated, does not seem to increase the operative risk, and might increase the locoregional control of the disease. The frequency of peritoneal involvement in relapsing patients underscores the need for a more effective systemic treatmen

    Cation distribution in manganese cobaltite spinels Co3−xMnxO4 (0 ≀ x ≀ 1) determined by thermal analysis

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    Thermogravimetric analysis was used in order to study the reduction in air of submicronic powders of Co3−x Mn x O4 spinels, with 0 ≀ x ≀ 1. For x = 0 (i.e. Co3O4), cation reduction occurred in a single step. It involved the CoIII ions at the octahedral sites, which were reduced to Co2+ on producing CoO. For 0 < x ≀ 1, the reduction occurred in two stages at increasing temperature with increasing amounts of manganese. The first step corresponded to the reduction of octahedral CoIII ions and the second was attributed to the reduction of octahedral Mn4+ ions to Mn3+. From the individual weight losses and the electrical neutrality of the lattice, the CoIII and Mn4+ ion concentrations were calculated. The distribution of cobalt and manganese ions present on each crystallographic site of the spinel was determined. In contrast to most previous studies that took into account either CoIII and Mn3+ or Co2+, CoIII and Mn4+ only, our thermal analysis study showed that Co2+/CoIII and Mn3+/Mn4+ pairs occupy the octahedral sites. These results were used to explain the resistivity measurements carried out on dense ceramics prepared from our powders sintered at low temperature (700–750 °C) in a Spark Plasma Sintering apparatus
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