1,794 research outputs found

    Interculturalidade: a complexidade constitutiva de políticas culturais

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    I Congresso Internacional América Latina e Interculturalidade: América Latina e Caribe: cenários linguístico-culturais contemporâneos, 07, 08 e 09 de novembro de 2013 - UNILAUma das lições que o texto de Michel Certeau (1984) “Walking in the city” nos ensina que “caminhar na cidade” do século XXI tornou­se absorvente devido às inúmeras vitrines que oferecem produtos identitários irrecusáveis, tanto por seus valores intrínsecos e por sua beleza, como pelos significados que geram pertencimentos e obrigações. A modernidade já havia produzido as narrativas baseadas nas metáforas da racionalidade, depois substituídas pela ingerência do social na formação das subjetividades humanas. Estas foram, posteriormente, desarrumadas, de um lado pelas propostas freudianas de um ego tripartite entre o id, o ego e superego e, por outro lado, pelos fios discursivos do poder (foucaultiano) que perpassam a organização social e a constituição das subjetividades que organizam o tecido social. Finalmente, nas últimas décadas do século XX surgem os estudos feministas e linguísticos que tingem o social com o político e o ideológico. E dentro desta complexidade que se discute nesta apresentação a questão das “políticas culturais” que visam a desenvolver interculturalidade(s). Procuram­se definir algumas metáforas que podem produzir sentidos nesta “caminhada na cidade” que, pelo menos aparentemente, parece cada vez mais globalizada. Levanta­se um conjunto de argumentos que definem esta caminhada como conflituosa e politicamente (política definida como ação) complexa, exigindo dos órgãos governamentais, das comunidades e dos indivíduos iniciativas que construam pontes ente “eu”, “nós” e “eles”, “dentro” e “fora”, desenhando, assim, novos mapas em que “raça”, “gênero”, “etnia”, “língua”, “cultura” e “fronteira” sejam ressignificados sem perderem os traços da “diferença”

    Structure, Scaling and Phase Transition in the Optimal Transport Network

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    We minimize the dissipation rate of an electrical network under a global constraint on the sum of powers of the conductances. We construct the explicit scaling relation between currents and conductances, and show equivalence to a a previous model [J. R. Banavar {\it et al} Phys. Rev. Lett. {\bf 84}, 004745 (2000)] optimizing a power-law cost function in an abstract network. We show the currents derive from a potential, and the scaling of the conductances depends only locally on the currents. A numerical study reveals that the transition in the topology of the optimal network corresponds to a discontinuity in the slope of the power dissipation.Comment: 4 pages, 3 figure

    Candidate molecular ions for an electron electric dipole moment experiment

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    This paper is a theoretical work in support of a newly proposed experiment (R. Stutz and E. Cornell, Bull. Am. Soc. Phys. 89, 76 2004) that promises greater sensitivity to measurements of the electron's electric dipole moment (EDM) based on the trapping of molecular ions. Such an experiment requires the choice of a suitable molecule that is both experimentally feasible and possesses an expectation of a reasonable EDM signal. We find that the molecular ions PtH+, HfH+, and HfF+ are suitable candidates in their low-lying triplet Delta states. In particular, we anticipate that the effective electric fields generated inside these molecules are approximately of 73 GV/cm, -17 GV/cm, and -18 GV/cm respectively. As a byproduct of this discussion, we also explain how to make estimates of the size of the effective electric field acting in a molecule, using commercially available, nonrelativistic molecular structure software.Comment: 25 pages, 3 figures, submitted to Physical Review

    Wave Mechanics of a Two Wire Atomic Beamsplitter

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    We consider the problem of an atomic beam propagating quantum mechanically through an atom beam splitter. Casting the problem in an adiabatic representation (in the spirit of the Born-Oppenheimer approximation in molecular physics) sheds light on explicit effects due to non-adiabatic passage of the atoms through the splitter region. We are thus able to probe the fully three dimensional structure of the beam splitter, gathering quantitative information about mode-mixing, splitting ratios,and reflection and transmission probabilities

    Correlation of bio- and magnetostratigraphy of Badenian sequences from western and northern Hungary

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    Lithological, magnetostratigraphic and paleontological (nannoplankton, foraminifers, molluscs) studies were carried out on the Badenian successions of boreholes Sopron-89, Nagylozs-1 and Sata-75 in Hungary. The correlations with the ATNTS2004 scale show that the Badenian sedimentation began during Chron C5Br thus the earliest Badenian deposits are missing in the sections. The first occurrence of Orbulina suturalis Bronnimann has been observed in Subchron C5Bn.1r, at 14.9 Ma. Although it is older than the interpolated age of 14.74 Ma in Chron C5ADr in the ATNTS2004, it is consistent with the age of 15.1 Ma obtained from recent calibration of planktonic foraminiferal bioevents. The base of the Bulimina-Bolivina Zone has been determined at 13.7 Ma in Chron C5ABr, and the Badenian/Sarmatian boundary is recorded within Chron C5AAn, at 13.15 Ma

    Optical receiver characterizations and corrections for ground-based and airborne measurements of spectral actinic flux densities

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    Solar actinic radiation in the ultraviolet and visible range (UV/VIS) perpetuates atmospheric photochemistry by inducing photolysis processes which form reactive radical species. Photolysis frequencies are rate constants that quantify the rates of photolysis reactions and therefore constitute important parameters for quantitative analyses. Photolysis frequencies are usually calculated from modelled or measured solar spectral actinic flux densities. Suitable measurement techniques are available, but measurement accuracy can suffer from non-ideal 2π or 4π solid-angle reception characteristics of the usually employed 2π optical receivers or receiver combinations. These imperfections, i.e. deviations from an angle-independent response, should be compensated for by corrections of the measured data. In this work, the relative angular sensitivities of four commonly used 2π quartz receivers were determined in the laboratory in a range 280–660 nm. Based on this information, the influence of the non-ideal responses on measured spectral actinic flux densities for ground-based and airborne applications was investigated for a wide range of atmospheric conditions. Spectral radiance distributions and contributions of direct, diffuse downward and diffuse upward spectral actinic flux densities were calculated with a radiative transfer model to derive the corrections. The intention was to determine the ranges of possible corrections under realistic measurement conditions and to derive simple parametrizations with reasonable uncertainties. For ground-based 2π measurements of downward spectral actinic flux densities, corrections typically range &lt;10 % dependent on wavelength and solar zenith angle, with 2 %–8 % uncertainties covering all atmospheric conditions. Corrections for 4π airborne measurements were determined for the platforms Zeppelin NT (New Technology) and HALO (High Altitude and Long Range Research Aircraft) in altitude ranges 0.05–2 and 0.2–15 km, respectively. Total, downward and upward spectral actinic flux densities were treated separately. In addition to various atmospheric conditions, different ground albedos and small (&lt;5∘) aircraft attitude variations were considered in the uncertainties, as well as aircraft headings with respect to the sun in the case of HALO. Corrections for total and downward spectral actinic flux densities again typically range &lt;10 % dependent on wavelength, solar zenith angle and altitude, with 2 %–10 % uncertainties covering all atmospheric conditions for solar zenith angles below 80∘. For upward spectral actinic flux densities, corrections were more variable and significantly greater, up to about −50 % at low altitudes and low ground albedos. A parametrization for corrections and uncertainties was derived using uncorrected ratios of upward / downward spectral actinic flux densities as input, applicable independent of atmospheric conditions for a given wavelength, solar zenith angle and altitude. The use was limited to conditions with solar zenith angles &lt;80∘ when direct sun radiation cannot strike upward- and downward-looking receivers simultaneously. Examples of research flights with the Zeppelin and HALO are discussed, as well as other approaches described in the literature.</p

    Inhibition of VEGF and Angiopoietin-2 to Reduce Brain Metastases of Breast Cancer Burden

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    For metastases in the central nervous system, angiogenesis enhances metastatic potential and promotes progression. Primary factors which drive vessel growth are vascular endothelial growth factor (VEGF) and angiopoietin-2. Preclinical models show inhibition of either factor reduces metastases spread and inhibits growth. This work sets out to answer two questions in a preclinical mouse model. First, whether the combined inhibition of VEGF and angiopoietin-2, reduces passive permeability and limits drug uptake into brain metastases; and second, whether this inhibition reduces metastases burden in brain. We observed combinatorial inhibition of VEGF and angiopoietin-2, decreased (p \u3c 0.05) angiogenesis and vascular branching in an aortic ring assay and decreased (p \u3c 0.05) endothelial wound closure times. Using a brain metastases of breast cancer model (induced by intracardiac injections of brain seeking MDA-MB-231Br cells or 4T1Br cells), we observed, similar to VEGF, angiopoetin-2 expression correlates to increased angiogenesis (p \u3c 0.05) and increased lesion permeability. To determine efficacy, animals were administered bevacizumab plus L1-10 (angiopoietin inhibitor) twice per week until neurological symptoms developed. Lesion permeability significantly decreased by ∼50% (p \u3c 0.05) compared to untreated lesions, but remained ∼25% greater (p \u3c 0.0%) than brain. In subsequent experiments, animals were administered similar regimens but sacrificed on day 32. The number of metastatic lesions developed was significantly (p \u3c 0.001) reduced in the bevacizumab group (56%) and combination group (86%). Lesions’ size was reduced in bevacizumab treated lesions (∼67%) and bevacizumab and L1-10 treated lesions (∼78%) developing area \u3c 0.5 mm2. In summary, combinatorial inhibition of VEGF and angiopoietin reduces lesion permeability and brain metastatic burden
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