997 resultados para Carta CUSUM-ln(S2)


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É unanimemente reconhecido que o conhecimento das origens e do desenvolvimento das sociedades humanas assume uma importância fundamental para toda a humanidade, permitindo-lhe reconhecer as suas raízes culturais e sociais. O património arqueológico constitui um testemunho essencial sobre as actividades humanas do passado. A sua protecção e gestão cuidadas são, por conseguinte, indispensáveis para permitir aos arqueólogos e a outros especialistas o seu estudo e interpretação em nome e para benefício das gerações presentes e futuras. A protecção deste património não pode basear-se exclusivamente nas técnicas da arqueologia. Exige uma base de conhecimentos e de competências profissionais e científicas mais alargadas. Alguns elementos do património arqueológico fazem parte de estruturas arquitectónicas, devendo nesse caso ser protegidos com respeito pelos critérios relativos ao património arquitectónico enunciados em 1964 na Carta de Veneza sobre a conservação e o restauro dos monumentos e sítios. Outros elementos fazem parte das tradições vivas das populações autóctones, cuja participação se torna essencial para a sua protecção e conservação. Por estas e outras razões, a protecção do património arqueológico deve assentar numa colaboração efectiva entre especialistas de diversas disciplinas. Exige ainda a cooperação dos serviços públicos, dos investigadores, das empresas privadas e do grande público.

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“Esperanças de Portugal” constitui-se como o primeiro grande esforço de teorização da visão profética do Quinto Império na obra de Pe. António Vieira. Fundamentada nas Trovas de Bandarra e na tradição judaica lida em Esperança de Israel, de Menassehben Israel, Pe. António Vieira evidencia nesta sua carta a estrutura universal, a temporalização, a espacialização geográfica e a sistematização hierofântica da consumação do Quinto Império.

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El presente documento recoge los resultados del estudio realizado sobre la Carta Andina para la Promoción y Protección de los Derechos Humanos, mejor conocida como la Carta Andina de Derechos Humanos, firmada por los Presidentes de los Estados Miembro de la Comunidad Andina de Naciones (CAN) el 26 de julio de 2002 en la ciudad de Guayaquil, Ecuador, en el marco de la Segunda Reunión de Presidentes Suramericanos. Examinaremos aquí el proceso de elaboración de este instrumento tan sui generis, así como su contenido según lo cual identificaremos su naturaleza, finalidad, características, aportes, límites, contradicciones, vacíos y potencialidades. La naturaleza de esta investigación, nos ha llevado a ubicar en el contexto de la integración subregional andina el discurso de los derechos humanos y los antecedentes históricos que han permitido su elaboración, así como los vínculos que la misma Comunidad ha establecido entre democracia, derechos humanos y desarrollo. Todo esto lo hemos hecho con la finalidad de responder a la pregunta central de nuestra investigación ¿Cuáles son los aportes de la Carta Andina de Derechos Humanos, para la promoción y defensa de los Derechos Humanos en el ámbito de la Comunidad Andina?

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The partitioning of minor trivalent actinides (An) from lanthanides (Ln) is one of the challenges in the chemical treatment of nuclear waste. The optimal ligand to carry out the separation of An(III) and Ln(III) using solvent extraction has to meet several important criteria: high selectivity towards the solute, chemical and radiolytic stability, stripping possibilities and recycling of the organic phase, high separation factors and good distribution ratio, to name just a few of them. A chronological line can be drawn along the development of each extraction ligand family and some milestones are emphasized in this overview. Further developments in organic synthesis of extracting ligands are expected.

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New lanthanide complexes of 2-hydroxynicotinic acid (H(2)nicO) [Ln(HnicO)(2)(mu-HnicO)(H2O)] (.) nH(2)O (Ln = Eu, Gd, Tb, Er, Tm) were prepared. The crystal structures of the [Tb(HnicO)(2)(g-HnicO)(H2O)] (.) 1.75H(2)O(1) and [Eu(HniCO)(2)(mu-HnicO)(H2O)] (.) 1.25H(2)O (2) complexes were determined by X-ray diffraction. The 2-hydroxynicotinate ligand coordinates through O,O-chelation to the lanthanide(III) ions as shown by X-ray diffraction and the infrared, Raman and NMR spectroscopy results. Photoluminescence measurements were performed for the Eu(III) and Tb(III) complexes. Lifetimes of 0.592 +/- 0.007 and 0.113 +/- 0.002 ms were determined for the Eu3+ and Tb3+ emitting states D-5(0) and D-5(4), respectively. A value around 30% was found for the D-5(0) quantum efficiency. The energy transfer mechanisms between the lanthanide ions and the ligands are discussed and compared with those observed in similar complexes involving the 3-hydroxypicolinate ligand based on the luminescence of the respective Gd3+-based complexes. (C) 2003 Published by Elsevier Ltd.

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Four new 6,6′-bis(1,2,4-triazin-3-yl)-2,2′-bipyridine (BTBP) ligands, which contain either additional alkyl groups on the pyridine rings or seven-membered aliphatic rings attached to the triazine rings, have been synthesized, and the effects of the additional alkyl substitution in the 4- and 4′-positions of the pyridine rings on their extraction properties with LnIII and AnIII cations in simulated nuclear waste solutions have been studied. The speciation of ligand 13 with some trivalent lanthanide nitrates was elucidated by 1H NMR spectroscopic titrations and ESI-MS. Although 13 formed both 1:1 and 1:2 complexes with LaIII and YIII, only 1:2 complexes were observed with EuIII and CeIII. Quite unexpectedly, both alkyl-substituted ligands 12 and 13 showed lower solubilities in certain diluents than the unsubstituted ligand CyMe4-BTBP. Compared to CyMe4-BTBP, alkyl-substitution was found to decrease the rates of metal-ion extraction of the ligands in both 1-octanol and cyclohexanone. A highly efficient (DAm > 10) and selective (SFAm/Eu > 90) extraction was observed for 12 and 13 in cyclohexanone and for 13 in 1-octanol in the presence of a phase-transfer agent. The implications of these results for the design of improved extractants for radioactive waste treatment are discussed.

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In this paper we show for the first time that calcite granules, produced by the earthworm Lumbricus terrestris, and commonly recorded at sites of archaeological interest, accurately reflect temperature and soil water δ18O values. Earthworms were cultivated in an orthogonal combination of two different (granule-free) soils moistened by three types of mineral water and kept at three temperatures (10, 16 and 20 ºC) for an acclimatisation period of three weeks followed by transfer to identical treatments and cultivation for a further four weeks. Earthworm-secreted calcite granules were collected from the second set of soils. δ18O values were determined on individual calcite granules (δ18Oc) and the soil solution (δ18Ow). The δ18Oc values reflect soil solution δ18Ow values and temperature, but are consistently enriched by 1.51 (±0.12) ‰ in comparison to equilibrium in synthetic carbonates. The data fit the equation 1000 ln α = [20.21 ± 0.92] (103 T-1) - [38.58 ± 3.18] (R2 = 0.95; n = 96; p < 0.0005). As the granules are abundant in modern soils, buried soils and archaeological contexts, and can be dated using U-Th disequilibria, the developed palaeotemperature relationship has enormous potential for application to Holocene and Pleistocene time intervals.

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The goal of this article is to introduce the reader to contemporary adult multilingual acquisition research within generative linguistics. In much the same way as monolingual and bilingual acquisition studies are approached within this paradigm, generative multilingual research focuses primarily on the psycholinguistic and cognitive aspects of the acquisition process. Herein, we critically present a panoramic view of the research questions and empirical work that have dominated this nascent field, taking the reader through several interrelated epistemological discussions that are at the vanguard of contemporary multilingual morphosyntax work. We finish this article with some thoughts looking towards the near future of adult multilingual acquisition studies.

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This study of UK retail milk identified highly significant variations in fat composition. The survey, conducted over 2 yr replicating summer and winter, sampled 22 brands, 10 of which indicated organic production systems. Results corroborate earlier farm-based findings considering fat composition of milk produced under conventional and organic management. Organic milk had higher concentrations of beneficial fatty acids (FA) than conventional milk, including total polyunsaturated fatty acids (PUFA; 39.4 vs. 31.8 g/kg of total FA), conjugated linoleic acid cis-9,trans-11 (CLA9; 7.4 v 5.6 g/kg of FA), and α-linolenic acid (α-LN; 6.9 vs. 4.4 g/kg of FA). As expected, purchase season had a strong effect on fat composition: compared with milk purchased in winter, summer milk had a lower concentration of saturated fatty acids (682 vs. 725 g/kg of FA) and higher concentrations of PUFA (37.6 vs. 32.8 g/kg of FA), CLA9 (8.1 vs. 4.7 g/kg of FA), and α-LN (6.5 vs. 4.6 g/kg of FA). Differences identified between sampling years were more surprising: compared with that in yr 2, milk purchased in year 1 had higher concentrations of PUFA (37.5 vs. 32.9 g/kg of FA), α-LN (6.0 vs. 5.1 g/kg of FA), and linoleic acid (19.9 vs. 17.5 g/kg of FA) and lower concentrations of C16:0 and C14:0 (332 vs. 357 and 110 vs. 118 g/kg of FA, respectively). Strong interactions were identified between management and season as well as between season and year of the study. As in the earlier farm studies, differences in fat composition between systems were greater for summer compared with winter milk. Large between-year differences may be due to changes in weather influencing milk composition through forage availability, quality, and intake. If climate change predictions materialize, both forage and dairy management may have to adapt to maintain current milk quality. Considerable variation existed in milk fat composition between brands.