1,429 research outputs found

    Saving the present in Brazil: Perspectives from collaborations with indigenous museums

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    This paper explores some of the challenges and benefits involved in the collaboration between the Museum of Archaeology and Ethnology of the University of SĂŁo Paulo, the India Vanuire Historical and Pedagogical Museum, and the Kaingang people of Vanuire, as well as some of the outcomes of these partnerships, such as the creation of the Kaingang Wowkriwig Museum. These experiences showed that working in collaboration with indigenous groups can be mutually beneficial and rewarding. The benefits include opportunities to empower the Kaingang to create and manage their own museums, and to exchange more effective preservation strategies, information about manufacturing technologies, as well as the original use and significance of objects. Moreover, the significance of objects whose value had diminished was revived by the new perspectives brought about by these inclusive approaches. The paper concludes that many other museums can act as agents of these processes but a prerequisite is a reconsideration of their relationships with indigenous groups and how the past can be redressed

    Unified scaling of the structure and loading of nanoparticles formed via diffusion-limited coalescence

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    The present study establishes the scaling laws describing the structure of spherical nanoparticles formed by diffusion-limited coalescence. We produced drug-loaded nanoparticles from a poly(ethylene glycol)-poly(d,l-lactic acid) diblock polymer (PEG-b-PLA) by the nanoprecipitation method using different types of micromixing chambers to explore multiple mixing regimes and characteristic times. We first show that the drug loading of the nanoparticles is not controlled by the mixing time but solely by the drug-to-polymer ratio (D:P) in the feed and the hydrophobicity of the drug scaled via the partition coefficient P. We then procure compelling evidence that particles formed via diffusion/coalescence exhibit a relative distribution of PEG blocks between the particle core and its shell that depends only on mixing conditions (not on D:P). Scaling laws of PEG relative distribution and chain surface density were derived in different mixing regimes and showed excellent agreement with experimental data. In particular, results made evident that PEG blocks entrapment in the core of the particles occurs in the slow-mixing regime and favors the overloading (above the thermodynamic limit) of the particles with hydrophilic drugs. The present analysis compiles effective guidelines for the scale up of nanoparticles structure and properties with mixing conditions, which should facilitate their future translation to medical and industrial settings

    Application of fuzzy logic and geostatistic in the analysis of the fertility of a soil under pasture

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    The objective of this research was to generate a representation of the chemical attributes of the soil, using fuzzy logic and geostatistic analysis as procedures of appropriate mapping to the representation of continuous phenomena. The area in study is located in the south of Espirito Santo state, county district of Alegre. The experiment was done in an Ultisol Yellow-Red loamy texture under cultivation of pasture Brachiaria decumbens The soil was sampled in the depth of 0-0,2 m, in the 64 points of a regular grid, with dimension of 90 x 90 m. The studied chemical attributes were K, Ca, Mg, Al. SB, T and V It took place a continuous classification (if the attributes, using the fuzzy logic The data were submitted to the descriptive analysis and, soon afterwards. the geostatistic analysis. through the semivariograms adjustment. The attributes presented moderate and high variability measured by CV. All of the attributes presented spatial dependence, demonstrated by the adjustment of the spherical and the exponential semivariogram The maps in study presented a mild representation of the limits of variation of the degrees of pertinence of the chemical attributes of the soil, turning them more representative The fuzzy logic associated to the geostatistic analysis is it suitable technique to be applied to generate a representation of soils attributes, which naturally present a gradual variation in the land.40332333

    Host Plant Record for the Fruit Flies, Anastrepha fumipennis and A. nascimentoi (Diptera, Tephritidae)

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    The first host plant record for Anastrepha fumipennis Lima (Diptera: Tephritidae) in Geissospermum laeve (Vell.) Baill (Apocynaceae) and for A. nascimentoi Zucchi found in Cathedra bahiensis Sleumer (Olacaceae) was determined in a host plant survey of fruit flies undertaken at the “Reserva Natural da Companhia Vale do Rio Doce”. This reserve is located in an Atlantic Rain Forest remnant area, in Linhares county, state of Espírito Santo, Brazil. The phylogenetic relationships of Anastrepha species and their hosts are discussed. The occurrence of these fruit fly species in relation to the distribution range of their host plants is also discussed

    MFGE8 does not influence chorio-retinal homeostasis or choroidal neovascularization in vivo

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    Purpose: Milk fat globule-epidermal growth factor-factor VIII (MFGE8) is necessary for diurnal outer segment phagocytosis and promotes VEGF-dependent neovascularization. The prevalence of two single nucleotide polymorphisms (SNP) in MFGE8 was studied in two exsudative or “wet” Age-related Macular Degeneration (AMD) groups and two corresponding control groups. We studied the effect of MFGE8 deficiency on retinal homeostasis with age and on choroidal neovascularization (CNV) in mice. Methods: The distribution of the SNP (rs4945 and rs1878326) of MFGE8 was analyzed in two groups of patients with “wet” AMD and their age-matched controls from Germany and France. MFGE8-expressing cells were identified in Mfge8+/− mice expressing ß-galactosidase. Aged Mfge8+/− and Mfge8−/− mice were studied by funduscopy, histology, electron microscopy, scanning electron microscopy of vascular corrosion casts of the choroid, and after laser-induced CNV. Results: rs1878326 was associated with AMD in the French and German group. The Mfge8 promoter is highly active in photoreceptors but not in retinal pigment epithelium cells. Mfge8−/− mice did not differ from controls in terms of fundus appearance, photoreceptor cell layers, choroidal architecture or laser-induced CNV. In contrast, the Bruch's membrane (BM) was slightly but significantly thicker in Mfge8−/− mice as compared to controls. Conclusions: Despite a reproducible minor increase of rs1878326 in AMD patients and a very modest increase in BM in Mfge8−/− mice, our data suggests that MFGE8 dysfunction does not play a critical role in the pathogenesis of AMD

    Higher spin interactions with scalar matter on constant curvature spacetimes: conserved current and cubic coupling generating functions

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    Cubic couplings between a complex scalar field and a tower of symmetric tensor gauge fields of all ranks are investigated on any constant curvature spacetime of dimension d>2. Following Noether's method, the gauge fields interact with the scalar field via minimal coupling to the conserved currents. A symmetric conserved current, bilinear in the scalar field and containing up to r derivatives, is obtained for any rank r from its flat spacetime counterpart in dimension d+1, via a radial dimensional reduction valid precisely for the mass-square domain of unitarity in (anti) de Sitter spacetime of dimension d. The infinite collection of conserved currents and cubic vertices are summarized in a compact form by making use of generating functions and of the Weyl/Wigner quantization on constant curvature spaces.Comment: 35+1 pages, v2: two references added, typos corrected, enlarged discussions in Subsection 5.2 and in Conclusion, to appear in JHE

    Effective action in a higher-spin background

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    We consider a free massless scalar field coupled to an infinite tower of background higher-spin gauge fields via minimal coupling to the traceless conserved currents. The set of Abelian gauge transformations is deformed to the non-Abelian group of unitary operators acting on the scalar field. The gauge invariant effective action is computed perturbatively in the external fields. The structure of the various (divergent or finite) terms is determined. In particular, the quadratic part of the logarithmically divergent (or of the finite) term is expressed in terms of curvatures and related to conformal higher-spin gravity. The generalized higher-spin Weyl anomalies are also determined. The relation with the theory of interacting higher-spin gauge fields on anti de Sitter spacetime via the holographic correspondence is discussed.Comment: 40 pages, Some errors and typos corrected, Version published in JHE
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