978 research outputs found

    Mechanistic studies on the photogeneration of o- and p-xylylenes from α,α'-dichloroxylenes

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    Two-colour two-laser techniques have unambiguously proved that photolysis of the o-/p-(chloromethyl)benzyl radical leads to the sequential two-photon generation of o-/pxylylene from α,α'-dichloro-o-/p-xylene.Perez Prieto, Julia, [email protected]

    Descolonizando Tiempo, Espacio y Conocimiento: El pueblo Kamëntšá en la encrucijada del patrimonio cultural

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    The dissertation is focused on three interrelated aspects: 1) the development of a decolonial theoretical framework and collaborative research methodology with the Kamëntšá people centred on the respect for Kamëntšá ethics, principles and social norms, and the consequent reconstruction, revitalization and dignification of Kamëntšá knowledge, arts, spirituality and notions of time and space; 2) the history and colonization processes of the Kamëntšá people and Uaman Tabanok, its ancestral lands, with a specific emphasis on the work of the Capuchin missionaries, particularly their concept of enculturation and how it transformed and resignified Kamëntšá culture and religion using its own arts, narratives and rituals which were in harmony with Christianity; and 3) the concept of “cultural heritage” and the role of academic disciplines, research practices, government institutions and cultural policies in the perpetuation of colonialism through the appropriation, interpretation, control and resignification of the objects, monuments and cultures of Indigenous peoples, and their consequent contribution to maintaining inequality, racism and historical social injustices.Gerda Henkel Foundation Portuguese Foundation for Science and Technology (FCT) German Academic Exchange Service (DAAD) COLING Project - EU Horizon 2020 program under the Marie Skłodowska-Curie Grant Agreement No 778384Heritage of Indigenous People

    Soft-sensor based on sliding modes for industrial raceway photobioreactors

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    Microalgae reactors provide an efficient and clean alternative for the production of biofuels, nutritional and cosmetic bioproducts, wastewater treatment, and mitigation of industrial gases to reduce greenhouse gas emissions. The main control objective in these systems is productivity optimisation. For this reason, real-time monitoring of key biological performance indicators affecting microalgae production such as microalgae growth rate, biomass concentration, dissolved oxygen, pH level or total inorganic carbon is crucial. However, there are no sufficiently robust solutions on the market to estimate or measure all of these variables, especially for open reactors on an industrial scale. This paper presents a new online state estimator, based on a robust sliding mode observer combined with a nonlinear dynamic model endowed with a minimum number of states to capture dynamics of key biological performance indicators. This soft-sensor has been verified with a realistic reactor model that has been experimentally tested. Simulations showed promising results in terms of accuracy (with mean values of the state estimation errors in the order of 10−4 g m−3 for the biomass concentration, 10−5 to 10−13 mol m−3 for the other states and deviations in the order of 10−4 g m−3 for the biomass concentration, 10−5 to 10−10 mol m−3 for the other states) and robustness with respect to signal noise, state deviations, initial errors and parametric uncertainty.Agencia Estatal de Investigación | Ref. PID2020-112709RB-C21Agencia Estatal de Investigación | Ref. PID2020-112709RB-C22Universidade de Vigo/CISU

    Crystal Structure and Physical Properties of U3T3Sn4 (T = Ni, Cu) Single-Crystals

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    Heat capacity experiments, crystal structure determination and transmission electron microscopy have been carried out on U3Cu3Sn4 single-crystals. U3Cu3Sn4 was confirmed to be a heavy-fermion antiferromagnet (TN=13(1) K) with a low temperature electronic heat capacity coefficient gamma=390 mJ/molUK2. Low temperature heat capacity experiments on a U3Ni3Sn4 single-crystal indicate that below 0.4 K there is a crossover between the previously observed non-Fermi liquid behavior and a Fermi liquid state.Comment: 12 pages (incl. 2 tables & 4 figures), to appear in Physica

    Repeated exposure to Lutzomyia intermedia sand fly saliva induces local expression of interferon-inducible genes both at the site of injection in mice and in human blood.

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    During a blood meal, Lutzomyia intermedia sand flies transmit Leishmania braziliensis, a parasite causing tegumentary leishmaniasis. In experimental leishmaniasis, pre-exposure to saliva of most blood-feeding sand flies results in parasite establishment in absence of any skin damages in mice challenged with dermotropic Leishmania species together with saliva. In contrast, pre-immunization with Lu. intermedia salivary gland sonicate (SGS) results in enhanced skin inflammatory exacerbation upon co-inoculation of Lu. intermedia SGS and L. braziliensis. These data highlight potential unique features of both L. braziliensis and Lu. intermedia. In this study, we investigated the genes modulated by Lu. intermedia SGS immunization to understand their potential impact on the subsequent cutaneous immune response following inoculation of both SGS and L. braziliensis. The cellular recruitment and global gene expression profile was analyzed in mice repeatedly inoculated or not with Lu. intermedia. Microarray gene analysis revealed the upregulation of a distinct set of IFN-inducible genes, an immune signature not seen to the same extent in control animals. Of note this INF-inducible gene set was not induced in SGS pre-immunized mice subsequently co-inoculated with SGS and L. braziliensis. These data suggest the parasite prevented the upregulation of this Lu. intermedia saliva-related immune signature. The presence of these IFN-inducible genes was further analyzed in peripheral blood mononuclear cells (PBMCs) sampled from uninfected human individuals living in a L. braziliensis-endemic region of Brazil thus regularly exposed to Lu. intermedia bites. PBMCs were cultured in presence or absence of Lu. intermedia SGS. Using qRT-PCR we established that the IFN-inducible genes induced in the skin of SGS pre-immunized mice, were also upregulated by SGS in PBMCs from human individuals regularly exposed to Lu. intermedia bites, but not in PBMCs of control subjects. These data demonstrate that repeated exposure to Lu. intermedia SGS induces the expression of potentially host-protective IFN-inducible genes

    Constraints on Z1-Z2 Mixing from the Decay Z1ee+Z1 \to e-e+ in the left-right Symmetric Model

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    We examine the decay of Z1Z_1 in electrons with recent data from LEP. The partial width Γ(Z1ee+)\Gamma(Z_1\to e^-e^+) is studied in the framework of a left-right symmetric model with standard electroweak corrections. Processes measured near the resonance has served to measure the neutral coupling constants very precisely, which is useful to set bounds on the parameters of the model. This partial decay occurs in the resonance zone. As a consecuence the process is independent of the mass of the additional Z2Z_2 heavy gauge boson which appears in this kind of models and so we have the mixing angle \f between the left and the right bosons as the only additional parameter. In this paper we take advantage of this fact to set a bound for \f: -9\times 10^{-3}\leq\f\leq 4\times 10^{-3}, which is in agreement with other constraints previously reported.Comment: 14 pages in Latex, 3 figures available on reques

    Multipulse phases in k-mixtures of Bose-Einstein condensates

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    For a competitive system of k coupled nonlinear Schroedinger equations we prove the existence, when the competition parameter is large, of positive radial solutions on R^N. We show that, when the competition parameter goes to infinity, the profile of each component separates, in many pulses, from the others. Moreover, we can prescribe the location of such pulses in terms of the oscillations of the changing-sign solutions of the scalar nonlinear Schroedinger equation. Within an Hartree-Fock approximation, this provides a theoretical indication of phase separation into many nodal domains for the k-mixtures of Bose-Einstein condensates.Comment: 21 page

    Density Waves in Layered Systems with Fermionic Polar Molecules

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    A layered system of two-dimensional planes containing fermionic polar molecules can potentially realize a number of exotic quantum many-body states. Among the predictions, are density-wave instabilities driven by the anisotropic part of the dipole-dipole interaction in a single layer. However, in typical multilayer setups it is reasonable to expect that the onset and properties of a density-wave are modified by adjacent layers. Here we show that this is indeed the case. For multiple layers the critical strength for the density-wave instability decreases with the number of layers. The effect depends on density and is more pronounced in the low density regime. The lowest solution of the instability corresponds to the density waves in the different layers being in-phase, whereas higher solutions have one or several adjancet layers that are out of phase. The parameter regime needed to explore this instability is within reach of current experiments.Comment: 7 pages, 4 figures. Final version in EPJD, EuroQUAM special issue "Cold Quantum Matter - Achievements and Prospects

    Bound Chains of Tilted Dipoles in Layered Systems

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    Ultracold polar molecules in multilayered systems have been experimentally realized very recently. While experiments study these systems almost exclusively through their chemical reactivity, the outlook for creating and manipulating exotic few- and many-body physics in dipolar systems is fascinating. Here we concentrate on few-body states in a multilayered setup. We exploit the geometry of the interlayer potential to calculate the two- and three-body chains with one molecule in each layer. The focus is on dipoles that are aligned at some angle with respect to the layer planes by means of an external eletric field. The binding energy and the spatial structure of the bound states are studied in several different ways using analytical approaches. The results are compared to stochastic variational calculations and very good agreement is found. We conclude that approximations based on harmonic oscillator potentials are accurate even for tilted dipoles when the geometry of the potential landscape is taken into account.Comment: 10 pages, 6 figures. Submitted to Few-body Systems special issue on Critical Stability, revised versio
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