969 resultados para rotational bands in Ir-176
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Pós-graduação em Química - IQ
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Medicina Veterinária - FCAV
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Planetary waves are key to large-scale dynamical adjustment in the global ocean as they transfer energy from the east to the west side of oceanic basins; they connect the forcing in the ocean interior with the variability at its boundaries: and they change the local heat content, thus coupling oceanic, atmospheric, and biological processes. Planetary waves, mostly of the first baroclinic mode, are observed as distinctive patterns in global time series of sea surface height anomaly (SSHA) and heat storage. The goal of this study is to compare and validate large-scale SSHA signals from coupled ocean-atmosphere general circulation Model for Interdisciplinary Research on Climate (MIROC) with TOPEX/POSEIDON satellite altimeter observations. The last decade of the models` time series is selected for comparison with the altimeter data. The wave patterns are separated from the meso- and large-scale SSHA signals by digital filters calibrated to select the same spectral bands in both model and altimeter data. The band-wise comparison allows for an assessment of the model skill to simulate the dynamical components of the observed wave field. Comparisons regarding both the seasonal cycle and the Rossby wave Held differ significantly among basins. When carried within the same basin, differences can occur between equal latitudes in opposite hemispheres. Furthermore, at some latitudes the MIROC reproduces biannual, annual and semiannual planetary waves with phase speeds and average amplitudes similar to those observed by the altimeter, but with significant differences in phase. (C) 2008 Elsevier Ltd. All rights reserved.
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The yolk sac is an embryonic membrane that is essential for the embryo's initial survival in many mammals. It also plays an important role in the production of proteins necessary for development. We studied proteins of the yolk sac in bovine embryos at up to 40 days of gestation. We examined the yolk sac of 17 bovine embryos at different gestational periods, measuring a-fetoprotein, alpha-1-antitrypsin, and transferrin. This experiment was carried out by Western blot technique, associated with electrophoresis on a 6% sodium dodecyl sulfate polyacrylamide gel. Mouse monoclonal antibody anti-human-alpha-fetoprotein, mouse antibody anti-human-transferrin and rabbit polyclonal anti-human-alpha-1-antitrypsin were used as primary antibodies, and conjugated peroxidase as a secondary antibody. We detected the three proteins in some of the yolk sac samples; however, the bands in some specimens (samples) were weak, maybe a result of poor antigen-antibody reaction, since the antibodies used in this study were not specific to bovine proteins. The fact that weak bands appeared might be due to a weak cross-reaction.
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Transgenic Citrus sinensis (L.) Osb. plants, cvs. Valencia and Hamlin, expressing Citrus tristeza virus (CTV) derived sequences were obtained by genetic transformation. The gene constructs were pCTV-CP containing the 25 kDa major capsid protein gene (CTV-CP), pCTV-dsCP containing the same CTV-CP gene in an intron-spliced hairpin construct, and pCTV-CS containing a 559 nt conserved region of the CTV genome. The transgenic lines were identified by PCR and the transgene integration was confirmed by Southern blot. Transgene mRNA could be detected in most transgenic lines containing pCTV-CP or pCTV-CS transgene. The mRNA of pCTV-dsCP transgene was almost undetectable, with very light bands in most analyzed plants. The transgene transcription appears to be closely linked to the type of gene construct. The virus challenge assays reveals that all transgenic lines were infected. However, it was possible to identify propagated clones of transgenic plants of both cultivars studied with a low virus titer, with values similar to the non-inoculated plants (negative control). These results suggested that the transgenic plants present some level of resistance to virus replication. The higher number of clones with low virus titer and where mRNA could not be detected or was presented in a very light band was found for pCTV-dsCP-derived transgenic lines.
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The weakening mechanisms involved in the collapse of complex impact craters are controversial. The Araguainha impact crater, in Brazil, exposes a complex structure of 40 km in diameter, and is an excellent object to address this issue. Its core is dominated by granite. In addition to microstructural observations, magnetic studies reveal its internal fabric acquired during the collapse phase. All granite samples exhibit impact-related planar deformation features (PDFs) and planar fractures (PFs), which were overprinted by cataclasis. Cataclastic deformation has evolved from incipient brittle fracturing to the development of discrete shear bands in the center of the structure. Fracture planes are systematically decorated by tiny grains (<10 mu m) of magnetite and hematite, and the orientation of magnetic lineation and magnetic foliation obtained by the anisotropies of magnetic susceptibility (AMS) and anhysteretic remanence (AAR) are perfectly coaxial in all studied sites. Therefore, we could track the orientation of deformation features which are decorated by iron oxides using the AMS and AAR. The magnetic fabrics show a regular pattern at the borders of the central peak, with orientations consistent with the fabric of sediments at the crater's inner collar and complex in the center of the structure. Both the cataclastic flow revealed from microstructural observations and the structural pattern of the magnetic anisotropy match the predictions from numerical models of complex impact structures. The widespread occurrence of cataclasis in the central peak, and its orientations revealed by magnetic studies indicate that acoustic fluidization likely operates at all scales, including the mineral scales. The cataclastic flow made possible by acoustic fluidization results in an apparent plastic deformation at the macroscopic scale in the core. (C) 2012 Elsevier B.V. All rights reserved.
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Ionic liquids based on 1-alkyl-3-methylimidazolium cations and the hydrogen sulfate (or bisulfate) anion, HSO4-, are much more viscous than ionic liquids with alkyl sulfates, RSO4-. The structural origin of the high viscosity of HSO4- ionic liquids is unraveled from detailed comparison of the anion Raman bands in 1-ethyl-3-methylimidazolium hydrogen sulfate and 1-butyl-3-methylimidazolium hydrogen sulfate with available data for simple HSO(4)(-) salts in crystalline phase, molten phase, and aqueous solution. Two Raman bands at 1046 and 1010 cm(-1) have been assigned as symmetric stretching modes nu(s)(S = O) of HSO4-, the latter being characteristic of chains of hydrogen-bonded anions. The intensity of this component increases in the supercooled liquid phase. For comparison purposes, Raman spectra of 1-ethyl-3-methylimidazolium ethyl sulfate and 1-butyl-3-methylimidazolium methyl sulfate have been also obtained. There is no indication of difference in the strength of hydrogen bond interactions of imidazolium cations with HSO4- or RSO4- anions. Raman spectra at high pressures, up to 2.6 GPa, are also discussed. Raman spectroscopy provides evidence that hydrogen-bonded anions resulting in anion-anion interaction is the reason for the high viscosity of imidazolium ionic liquids with HSO4-. If the ionic liquid is exposed to moisture, these structures are disrupted upon absorption of water from the atmosphere.
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This work presents two potential metallo-drugs, the ionic (C17H19FN3O3)(3)[RuCl6]center dot 3H(2)O (1) and the coordination [Ru(C17H17FN3O3)(3)]center dot 4H(2)O (2) compounds, obtained by the combination of ruthenium(III) and ciprofloxacin in different synthetic conditions. The ESI MS spectrum of 1 displayed a main peak at m/z = 994.6, assigned to the gaseous phase adduct (ciprofloxacin)(3)center dot H+, while 2 featured peaks at m/z 1093.3 and 547.1 ascribed to [Ru(C17H17FN3O3)(3)center dot H+-4H(2)O](+) and [Ru(C17H17FN3O3)(3)center dot 2H(+)-4H(2)O](2+). Thermal analysis corroborated the proposed water content for both complexes. Absorption spectra of the compounds in aqueous medium are dominated by ciprofloxacin transitions in the UV region but displayed weak bands in the visible region, assigned to ligand field transitions. The cyclic voltammograms of 2 exhibited a quasi-reversible process ascribed to the Ru(II)/(III) redox pair at -0.25V (vs. SHE) while 1 displayed this process at -0.11 V, showing that the central ruthenium ion is stabilized in the (III) oxidation state by the coordination to the hard oxygen atoms of ciprofloxacin. The solubility of 1 is pH dependent (as well as free ciprofloxacin) while 2 is fully water soluble and stable under physiological pH for at least 48 h. The compounds are also stable under incubation conditions (stomach pH and 37 degrees C) without significant pH lowering. An interaction study of 2 with ct-DNA showed a value of K-b = 2.47 (+/- 0.89) x 10(4) mol(-1) L for the intrinsic binding constant.
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Máster Oficial en Gestión Costera
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Zusammenfassung: Thema dieser Arbeit ist der Einfluss von elektrischen Feldern auf die Viskosität nematischer Flüssigkristalle sowie isotroper Polymerlösungen.Für zwei thermotrope nematische Flüssigkristalle, 4-(trans-4'-n-Pentylcyclohexyl)-benzonitril (PCH-5) und 4-n-Pentyl-4'-cyanobiphenyl (5CB), wurde die Viskosität mit elektrorheologischen Messungen in Abhängigkeit von Feldstärke und Scherrate bestimmt. Alle Messwerte kommen bei Auftragung gegen E?/? auf einer Masterkurve zu liegen. Die Anpassung dieser Daten mit einer auf der Theorie von Ericksen und Leslie basierenden Gleichung liefert gleichzeitig die Scherviskositäten ? und ? sowie die Rotationsviskosität ? in guter Übereinstimmung mit Literaturwerten. Elektrorheologische Messungen stellen somit eine Methode zur Bestimmung dieser Viskositätskoeffizienten für Nematen dar, wenn diese eine ausreichend große positive dielektrische Anisotropie aufweisen. Bei den isotropen Polymerlösungen ließ sich der elektrorheologische Effekt des Systems Decalin/Polystyrol im Bereich der Entmischungstemperatur klären. Während im Ein-Phasen-Gebiet nur eine geringe Viskositätsänderung im E-Feld aufgrund elektrohydrodynamischer Strömungen zu beobachten ist, tritt unterhalb der Entmischungstemperatur ein deutlicher, aber nicht reproduzierbarer ER-Effekt auf. Dieser ist auf einen Einfluss des E-Felds auf die Zwei-Phasen-Morphologie zurückzuführen.Für das System Diethylbenzol/Isopentylcellulose wurde ein negativer elektrorheologischer Effekt auf die Dissoziation von assoziierten Polymermolekülen zurückgeführt. Die Dissoziation erfolgt aufgrund der Wirkung des elektrischen Feldes auf freie Ladungen.
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This research undertakes to provide a typology of multipolar systems. Multipolarity plays a key role in IR theory, for it is strictly associated with the history of European politics since the seventeenth century to the end of World War Two. Despite wide investigation, one can doubt the matter has received a definitive treatment. Trouble is that current studies often consider multipolarity as a one-dimensional concept. They obviously reckon that multipolarism is substantially different from other systems and deserves attention, but generally fail to distinguish between different types of multipolar systems (the few exceptions are listed in chapter one). The history of international politics tells us a different story. Multipolar power systems may share some general characteristics, but they also show a wide array of difference, and understanding this difference requires a preliminary work of classification. That is the purpose of the present study. The work is organized as follows. In chapter one, we provide a cursory review of the literature on multipolarity, with particular reference to the work of Duncan Snidal and Joseph Grieco. Then we propose a four-cell typology of multipolar systems to be tested via historical analysis. The first type, hegemony, is best represented by European international system to the time of Napoleonic France, and is discussed in chapter two. Type number two is the traditional concert of Europe, which history is detailed in chapter three. Type number three is the reversal of alliances, which closest example, the diplomatic revolution of 1756, is discussed in chapter four. Finally, chapter five is devoted to the chain-gang system, and the European politics from Bismarck’s late years to World War One represents a good illustration of how it works. In chapter six we proceed to draw a first evaluation of the main results achieved in the previous chapters, in order to see if, and to what extent, our typology serves the purpose of explaining the nature of multipolar systems.
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In dieser Arbeit wurden neuartige substituierte N-Benzylbenzothiazoliumhexa-fluorophosphate und –antimonate synthetisiert und hinsichtlich ihre Wirksamkeit als photo- und thermolatente Initiatoren für Epoxidpolymerisationen untersucht. Zur Synthese der Benzothiazoliumderivate wurden zunächst substituierte Benzothiazole nach verschiedenen Verfahren hergestellt, diese mit den entsprechenden Benzylbromiden quaternisiert und die N-quaternären Bromide zu den Hexafluorophosphaten bzw. –antimonaten umgesalzt. Neben den niedermolekularen Benzothiazoliumsalzen wurden auch Copolymere mit dieser Struktur in der Seitenkette durch radikalische Copolymerisation vinylsubstituierter N-quaternärer Benzothiazoliumsalze mit MMA hergestellt. Sowohl die niedermolekularen als auch die polymergebundenen Benzothiazoliumhexafluorophosphate erwiesen sich als effektive direkte kationische Photo- und Thermoinitiatoren für die Polymerisation von Epoxiden. Durch die Einführung auxochromer Ethergruppierungen konnte eine bathochrome Verschiebung der UV-Absorptionswellenlänge des energieärmsten elektronischen Überganges erreicht werden. Kinetische IR-Studien der kationischen Polymerisation von Glycidylphenylether (GPE) im Nassfilm unter Bestrahlung in Gegenwart der hergestellten Benzothiazoliumsalze als Photoinitiatoren zeigten dass durch die so erreichte verbesserte Ausnutzung der einwirkenden Strahlung die kationische Photoinitiatoreffektivität deutlich gesteigert werden konnte. Der Zusatz eines photolytischen Radikalbildners führte zu einer weiteren Steigerung der Photopolymerisationsgeschwindigkeit und zu einer Umkehr der beobacheteten Initiatoreffektivitäten. UV-, 1H NMR-, sowie MALDI-TOF- Untersuchungen, sowie die vollständige Unterdrückung der Photopolymerisation durch den Protonenfänger DBP deuten auf die photolytische Generierung von Protonen als initiierende Spezies der photokationischen Polymerisation und DSC- und 1H-NMR Ergebnisse auf die thermische Generierung von Benzylkationen als initiierende Spezies der thermischen Polymerisation hin.
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The ever increasing demand for new services from users who want high-quality broadband services while on the move, is straining the efficiency of current spectrum allocation paradigms, leading to an overall feeling of spectrum scarcity. In order to circumvent this problem, two possible solutions are being investigated: (i) implementing new technologies capable of accessing the temporarily/locally unused bands, without interfering with the licensed services, like Cognitive Radios; (ii) release some spectrum bands thanks to new services providing higher spectral efficiency, e.g., DVB-T, and allocate them to new wireless systems. These two approaches are promising, but also pose novel coexistence and interference management challenges to deal with. In particular, the deployment of devices such as Cognitive Radio, characterized by the inherent unplanned, irregular and random locations of the network nodes, require advanced mathematical techniques in order to explicitly model their spatial distribution. In such context, the system performance and optimization are strongly dependent on this spatial configuration. On the other hand, allocating some released spectrum bands to other wireless services poses severe coexistence issues with all the pre-existing services on the same or adjacent spectrum bands. In this thesis, these methodologies for better spectrum usage are investigated. In particular, using Stochastic Geometry theory, a novel mathematical framework is introduced for cognitive networks, providing a closed-form expression for coverage probability and a single-integral form for average downlink rate and Average Symbol Error Probability. Then, focusing on more regulatory aspects, interference challenges between DVB-T and LTE systems are analysed proposing a versatile methodology for their proper coexistence. Moreover, the studies performed inside the CEPT SE43 working group on the amount of spectrum potentially available to Cognitive Radios and an analysis of the Hidden Node problem are provided. Finally, a study on the extension of cognitive technologies to Hybrid Satellite Terrestrial Systems is proposed.