State and parameter estimation approach to monitoring AGR nuclear core

This work concerns with the problem of monitoring an Advanced Gas-cooled Nuclear Reactor (AGR) core. This plant (figure 1) makes use of the heat given by the nuclear efficient reaction to produce electricity by means of steam turbines. These are driven by steam, which is heated, from the AGR gas using a heat exchanger. One of the advantages of a gas cooled reactor is the high temperature that the gas can achieve so that when it is used in conjunction with the heat exchanger and steamed turbine the thermal efficiency is very high

Constraining the Milky Way potential using the dynamical kinematic substructures

We present a method to constrain the potential of the non-axisymmetric components of the Galaxy using the kinematics of stars in the solar neighborhood. The basic premise is that dynamical substructures in phase-space (i.e. due to the bar and/or spiral arms) are associated with families of periodic or irregular orbits, which may be easily identified in orbital frequency space. We use the "observed" positions and velocities of stars as initial conditions for orbital integrations in a variety of gravitational potentials. We then compute their characteristic frequencies, and study the structure present in the frequency maps. We find that the distribution of dynamical substructures in velocity- and frequency-space is best preserved when the integrations are performed in the "true" gravitational potential.Comment: 2 pages, 4 figures, to appear in the proceedings of "Assembling the Puzzle of the Milky Way", Le Grand Bornand (Apr. 17-22, 2011

A de Finetti representation for finite symmetric quantum states

Consider a symmetric quantum state on an n-fold product space, that is, the state is invariant under permutations of the n subsystems. We show that, conditioned on the outcomes of an informationally complete measurement applied to a number of subsystems, the state in the remaining subsystems is close to having product form. This immediately generalizes the so-called de Finetti representation to the case of finite symmetric quantum states.Comment: 22 pages, LaTe

Spiral arm crossings inferred from ridges in Gaia stellar velocity distributions

The solar neighborhood contains disc stars that have recently crossed spiral arms in the Galaxy. We propose that boundaries in local velocity distributions separate stars that have recently crossed or been perturbed by a particular arm from those that haven't. Ridges in the stellar velocity distributions constructed from the second Gaia data release trace orbits that could have touched nearby spiral arms at apocentre or pericentre. The multiple ridges and arcs seen in local velocity distributions are consistent with the presence of multiple spiral features and different pattern speeds and imply that the outer Galaxy is flocculent rather than grand design.Comment: For a movie https://youtu.be/5nbtNYDobc

Sequence randomness and polymer collapse transitions

Contrary to expectations based on Harris' criterion, chain disorder with frustration can modify the universality class of scaling at the theta transition of heteropolymers. This is shown for a model with random two-body potentials in 2D on the basis of exact enumeration and accurate Monte Carlo results. When frustration grows beyond a certain finite threshold, the temperature below which disorder becomes relevant coincides with the theta one and scaling exponents definitely start deviating from those valid for homopolymers.Comment: 4 pages, 4 eps figure

Spontaneous self-assembly of an unsymmetric trinuclear triangular copper(II) pyrazolate complex, [Cu3(μ3-OH)(μ-pz) 3(MeCOO)2(Hpz)] (Hpz = pyrazole). Synthesis, experimental and theoretical characterization, reactivity, and catalytic activity

The almost quantitative formation of the triangular trinuclear copper derivative [Cu3(μ3-OH)(μ-pz)3(MeCOO) 2(Hpz)] (1) (Hpz = pyrazole), has been simply achieved by adding Hpz to an ethanol solution of Cu(MeCOO)2·H2O. An X-ray molecular structure determination shows that 1 is completely unsymmetric and that trinuclear units result assembled in an extended bidimensional network formed through acetate bridges and hydrogen bonds. EPR and magnetic measurements are consistent with the presence of a single unpaired electron. Theoretical density functional calculations carried out for S = 1/2 provide a thorough description of the electronic structure of 1, allowing a detailed assignment of its UV-vis absorption spectrum. Compound 1 reacts with MeONa, yielding [Cu 3(μ3-OH)(μ-pz)3(MeCOO)(MeO)(Hpz)] (2) and [Cu3(μ3-OH)(μ-pz)3(MeO) 2(Hpz)] (3) through the substitution of one and two acetate ions, respectively, with MeO- ion(sS). The spontaneous self-assembly of the triangular trinuclear Cu3 moiety seems to occur only with pyrazole as can be inferred by the results obtained in the reactions of copper(II) acetate with some substituted pyrazoles leading to the formation of mononuclear [Cu(MeCOO)2(L)2] (4-8) and dinuclear [Cu(MeCOO) 2(L)]2 (9-11) (L = substituted pyrazole) compounds. Also the presence of acetate ions seems to play a leading role in determining the formation of the trinuclear triangular arrangement, as indicated by the formation of a mononuclear derivative, [Cu(CF3COO) 2(Hpz)]2 (compound 12), in the reaction of copper(II) trifluoroacetate with pyrazole. Compounds 1-3, as well as some other mono- and dinuclear copper(II)-substituted pyrazole complexes, have been tested as catalyst precursors in cyclopropanation reaction, observing the formation of products in a syn:anti ratio opposite that normally reported

Nitinol Carbofilm coated stents for peripheral applications: Study in the porcine model

Purpose: Testing the safety and foreign body reaction (FBR) of a nitinol self-expandable carbon-coated stent system in the porcine animal model at different follow-up (FU) periods. Methods: Fifteen minipigs received 30 carbon-coated self-expandable nitinol stents in iliac arteries. Explants were carried out at 7 (3 animals), 30 (4 animals), 90 (4 animals) and 180 (4 animals) day FU, for evaluation of acute, sub-acute and chronic biological response to the implanted devices. Histological, immunohistochemical, histomorphometric and scanning electron microscopy (SEM) analyses were performed to assess inflammatory reaction, endothelialization process, neointimal growth and cellular composition. Results: Thirty stents were successfully implanted. No mural thrombi were observed at gross examination or by angiography. Histologically no significant inflammatory reaction was detected: the stents appeared covered by a thin monolayer of endothelial cells even at 7 day FU. The neointima presented homogeneous growth and moderate thickness after 30, 90 and 180 days explants (0.38± 0.36 mm, 0.33± 0.30 mm, 0.27± 0.25 mm respectively). Internal and external elastic laminae were intact in 95% of stented arteries. Histological data validations of vessel endothelialization was obtained with SEM for the seven day follow-up group. Conclusions: This study showed good remarkable technical performances, minimal FBR and biocompatibility comparable with other available pre-clinical experimentation

Coordination Chemistry of the (eta(6)-p-Cymene)ruthenium(II) Fragment with Bis-, Tris-, andTetrakis(pyrazol-1-yl)borate Ligands: Synthesis, Structural, Electrochemical, and CatalyticDiastereoselective Nitroaldol Reaction Studies

Novel [Ru(eta(6)-p-cymene)(kappa(2)-L)X] and [Ru(eta(6)-p-cymene)(kappa(3)-L)]X center dot nH(2)O complexes (L = bis-, tris-, or tetrakis-pyrazolylborate; X = Cl, N-3, PF6, or CF3SO3) are prepared by treatment of [Ru(eta(6)-p-cymene)Cl-2](2) with poly-(pyrazolyl)borate derivatives [M(L)] (L in general; in detail L = Ph(2)Bp = diphenylbis-(pyrazol-1-yl)borate; L = Tp = hydrotris(pyrazol-1-yl)borate; L = pzTp = tetrakis(pyrazol-1-yl)borate; L = Tp(4Bo) = hydrotris(indazol-1-yl)borate, L = T-p4Bo,T-5Me = (5-methylindazol-1-yl)borate; L = Tp(Bn,4Ph) = hydrotris(3-benzyl-4-phenylpyrazol-1-yl)borate; M = Na, K, or TI) and characterized by analytical and spectral data (IR, ESIMS, H-1 and C-13 NMR). The structures of [Ru(eta(6)-p-cymene)(Ph(2)Bp)Cl] (1) and [Ru(eta(6)-p-cymene)(Tp)Cl] (3) have been established by single-crystal X-ray diffraction analysis. Electrochemical studies allowed comparing the electron-donor characters of Tp and related ligands and estimating the corresponding values of the Lever E-L ligand parameter. The complexes [Ru(eta(6)-p-cymene)-(kappa(2)-L)X] and [Ru(eta(6)-p-cymene)(kappa(3)-L)]X center dot nH(2)O act as catalyst precursors for the diastereoselective nitroaldol reaction of benzaldehyde and nitroethane to the corresponding beta-nitroalkanol (up to 82% yield, at room temperature) with diastereoselectivity toward the formation of the threo isomer

Interaction of Iron II Complexes with B-DNA. Insights from Molecular Modeling, Spectroscopy, and Cellular Biology

We report the characterization of the interaction between B-DNA and three terpyridin iron II complexes. Relatively long time-scale molecular dynamics is used in order to characterize the stable interaction modes. By means of molecular modeling and UV-vis spectroscopy, we prove that they may lead to stable interactions with the DNA duplex. Furthermore, the presence of larger π-conjugated moieties also leads to the appearance of intercalation binding mode. Non-covalent stabilizing interactions between the iron complexes and the DNA are also characterized and evidenced by the analysis of the gradient of the electronic density. Finally, the structural deformations induced on the DNA in the different binding modes are also evidenced. The synthesis and chemical characterization of the three complexes is reported, as well as their absorption spectra in presence of DNA duplexes to prove the interaction with DNA. Finally, their effects on human cell cultures have also been evidenced to further enlighten their biological effects