41 research outputs found
Generalizations of Poisson structures related to rational Gaudin model
The Poisson structure arising in the Hamiltonian approach to the rational
Gaudin model looks very similar to the so-called modified Reflection Equation
Algebra. Motivated by this analogy, we realize a braiding of the mentioned
Poisson structure, i.e. we introduce a "braided Poisson" algebra associated
with an involutive solution to the quantum Yang-Baxter equation. Also, we
exhibit another generalization of the Gaudin type Poisson structure by
replacing the first derivative in the current parameter, entering the so-called
local form of this structure, by a higher order derivative. Finally, we
introduce a structure, which combines both generalizations. Some commutative
families in the corresponding braided Poisson algebra are found.Comment: LATEX, 16 p
Time and frequency transfer over optical networks
This paper aims to summarize and express network requirements of time and frequency transfer over optical networks performed in National Research and Education networks of France and Czech Republic. Time transfer experiment in Czech Republic converts microwave output frequency of cesium atomic clocks into train of optical pulses that carries accurate time over all-optical network with two network domains. Frequency transfer experiment references optical comb etalon to frequency of atomic clock. An optical frequency of optical comb is then sent throughout optical network in a single bidirectional channel. The paper highlights advantages and challenges of both transfer approaches
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High-Performance, Lightweight, and Flexible Thermoplastic Polyurethane Nanocomposites with Zn2+-Substituted CoFe2O4 Nanoparticles and Reduced Graphene Oxide as Shielding Materials against Electromagnetic Pollution
The development of flexible, lightweight, and thin high-performance electromagnetic interference shielding materials is urgently needed for the protection of humans, the environment, and electronic devices against electromagnetic radiation. To achieve this, the spinel ferrite nanoparticles CoFe2O4 (CZ1), Co0.67Zn0.33Fe2O4 (CZ2), and Co0.33Zn0.67Fe2O4 (CZ3) were prepared by the sonochemical synthesis method. Further, these prepared spinel ferrite nanoparticles and reduced graphene oxide (rGO) were embedded in a thermoplastic polyurethane (TPU) matrix. The maximum electromagnetic interference (EMI) total shielding effectiveness (SET) values in the frequency range 8.2-12.4 GHz of these nanocomposites with a thickness of only 0.8 mm were 48.3, 61.8, and 67.8 dB for CZ1-rGO-TPU, CZ2-rGO-TPU, and CZ3-rGO-TPU, respectively. The high-performance electromagnetic interference shielding characteristics of the CZ3-rGO-TPU nanocomposite stem from dipole and interfacial polarization, conduction loss, multiple scattering, eddy current effect, natural resonance, high attenuation constant, and impedance matching. The optimized CZ3-rGO-TPU nanocomposite can be a potential candidate as a lightweight, flexible, thin, and high-performance electromagnetic interference shielding material
Cu–Ni nanoalloy phase diagram – Prediction and experiment
The Cu-Ni nanoalloy phase diagram respecting the nanoparticle size as an extra variable was calculated by the CALPHAD method. The samples of the Cu-Ni nanoalloys were prepared by the solvothermal synthesis from metal precursors. The samples were characterized by means of dynamic light scattering (DLS), infrared spectroscopy (IR), inductively coupled plasma optical emission spectroscopy (ICP/OES), transmission electron microscopy (TEM, HRTEM), and differential scanning calorimetry (DSC). The nanoparticle size, chemical composition, and Cu-Ni nanoparticles melting temperature depression were obtained. The experimental temperatures of melting of nanoparticles were in good agreement with the theoretical CALPHAD predictions considering surface energy.FázovĂ˝ diagram nanoslitiny Cu-Ni respektujĂcĂ velikost nanočástic jako dalšà promÄ›nnĂ© byl vypoÄŤten metodou CALPHAD. Vzorky Cu-Ni nanoslitin byly pĹ™ipraveny solvotermálnĂ syntĂ©zou z prekurzorĹŻ kovĹŻ. Tyto vzorky byly charakterizovány pomocĂ dynamickĂ©ho rozptylu svÄ›tla (DLS), infraÄŤervenĂ© spektroskopie (IR) s indukÄŤnÄ› vázanou plazmou a optickou emisnĂ spektroskopiĂ (ICP / OES), transmisnĂ elektronovou mikroskopiĂ (TEM, HRTEM) a diferenciálnĂ skenovacĂ kalorimetriĂ (DSC). Velikost nanočástic, chemickĂ© sloĹľenĂ a Cu-Ni deprese teploty tánĂ nanočástic byly zĂskány experimentálnÄ› a v dobrĂ© shodÄ› s teoretickou pĹ™edpovÄ›dĂ metodou CALPHAD s uváženĂm povrchovĂ© energie nanočástic
Natalizumab treatment shows low cumulative probabilities of confirmed disability worsening to EDSS milestones in the long-term setting.
Abstract Background Though the Expanded Disability Status Scale (EDSS) is commonly used to assess disability level in relapsing-remitting multiple sclerosis (RRMS), the criteria defining disability progression are used for patients with a wide range of baseline levels of disability in relatively short-term trials. As a result, not all EDSS changes carry the same weight in terms of future disability, and treatment benefits such as decreased risk of reaching particular disability milestones may not be reliably captured. The objectives of this analysis are to assess the probability of confirmed disability worsening to specific EDSS milestones (i.e., EDSS scores ≥3.0, ≥4.0, or ≥6.0) at 288 weeks in the Tysabri Observational Program (TOP) and to examine the impact of relapses occurring during natalizumab therapy in TOP patients who had received natalizumab for ≥24 months. Methods TOP is an ongoing, open-label, observational, prospective study of patients with RRMS in clinical practice. Enrolled patients were naive to natalizumab at treatment initiation or had received ≤3 doses at the time of enrollment. Intravenous natalizumab (300 mg) infusions were given every 4 weeks, and the EDSS was assessed at baseline and every 24 weeks during treatment. Results Of the 4161 patients enrolled in TOP with follow-up of at least 24 months, 3253 patients with available baseline EDSS scores had continued natalizumab treatment and 908 had discontinued (5.4% due to a reported lack of efficacy and 16.4% for other reasons) at the 24-month time point. Those who discontinued due to lack of efficacy had higher baseline EDSS scores (median 4.5 vs. 3.5), higher on-treatment relapse rates (0.82 vs. 0.23), and higher cumulative probabilities of EDSS worsening (16% vs. 9%) at 24 months than those completing therapy. Among 24-month completers, after approximately 5.5 years of natalizumab treatment, the cumulative probabilities of confirmed EDSS worsening by 1.0 and 2.0 points were 18.5% and 7.9%, respectively (24-week confirmation), and 13.5% and 5.3%, respectively (48-week confirmation). The risks of 24- and 48-week confirmed EDSS worsening were significantly higher in patients with on-treatment relapses than in those without relapses. An analysis of time to specific EDSS milestones showed that the probabilities of 48-week confirmed transition from EDSS scores of 0.0–2.0 to ≥3.0, 2.0–3.0 to ≥4.0, and 4.0–5.0 to ≥6.0 at week 288 in TOP were 11.1%, 11.8%, and 9.5%, respectively, with lower probabilities observed among patients without on-treatment relapses (8.1%, 8.4%, and 5.7%, respectively). Conclusions In TOP patients with a median (range) baseline EDSS score of 3.5 (0.0–9.5) who completed 24 months of natalizumab treatment, the rate of 48-week confirmed disability worsening events was below 15%; after approximately 5.5 years of natalizumab treatment, 86.5% and 94.7% of patients did not have EDSS score increases of ≥1.0 or ≥2.0 points, respectively. The presence of relapses was associated with higher rates of overall disability worsening. These results were confirmed by assessing transition to EDSS milestones. Lower rates of overall 48-week confirmed EDSS worsening and of transitioning from EDSS score 4.0–5.0 to ≥6.0 in the absence of relapses suggest that relapses remain a significant driver of disability worsening and that on-treatment relapses in natalizumab-treated patients are of prognostic importance
Vyuziti druhotne energie zbytkovych propelentu
Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi
Naucny videoprogram zamereny na vypoctove-experimentalni metody dimenzovani ve strojirenstvi.
A systemic interconnection of calculation and experimental methods when solving exacting problems connected with structure optimization of complex machinery products is demonstrated on examples with an audio-visual popular-scientific programme. The programme is above all determined for teaching needs, as visual aid at lessons at secondary schools and technical universities. Any other use of this programme is possible in the frame of popular technical TV programmes for the wide public.Supplement: 1 videocasette (film Experimental support of the development of dynamically loaded constructions).Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi