948 resultados para Tema para versos I e II


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A Cambridge Structural Database (CSD) analysis on halogen center dot center dot center dot halogen contacts (X...X) in organic crystals has been carried out to review the classification criteria for type I, type II, and quasi type I/II halogen interactions. Trends observed in previous CSD analyses of the phenomenon are reinforced in the present study. The manner in which these interactions are manifested in cocrystals of 4-bromobenzamide and dicarboxylic acid is examined. The design strategy for these cocrystals uses synthon theory and follows from an understanding of the crystal structures of gamma-hydroquinone and a previously studied set of 4-hydroxybenzamide dicarboxylic acid cocrystals, making use of Br/OH isostructurality. All cocrystals are obtained by clean insertion of dicarboxylic acids between 4-bromobenzamide molecules. The strategy is deliberate and the prediction of synthons done well in advance, as evidenced from the robustness of the acid-amide heterosynthons in all nine crystal structures, with no aberrant structures in the crystallization experiments. Formation of the acid-amide synthon in these cocrystals is identified with IR spectroscopy. The packing in these cocrystals can be distinguished in terms of whether the Br...Br interactions are type I or II. Eight sets of dimorphs were retrieved from the CSD, wherein the basis of the polymorphism is that one crystal has a type I Br...Br interaction, while the other has a type II interaction.

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Rui de Pina nasceu na cidade de Guarda, provavelmente em 1440, e morreu em Lisboa, por volta de 1522. Ocupou vários cargos de importância e destaque, entre eles os de cronista-mor do reino e de guarda-mor da Torre do Tombo. Como cronista-mor de Portugal, escreveu as biografias de Sancho I, Afonso II, Sancho II, Afonso II, D. Dinis, Afonso IV, Afonso V e D. João II. A descoberta , recentemente, de duas cópias de uma obra quatrocentista contendo as histórias dos sete primeiros reis de Portugal, isto é, de Sancho I a Afonso IV, indica que as Chronicas destes reis escritas por Rui de Pina não passavam de uma refundição daquelas. Como historiador, o autor tem despertado opiniões polêmicas: uns o acusam de mal-informado e desonesto ; outros valorizam a sua capacidade de compreender os eventos de seu tempo, ainda que sob uma visão absolutista. Trata-se de uma “esplêndida edição , adornada de escudos alegóricos com armas reais portuguesas no centro – que encabeçam as dedicatórias -, de artísticas letras iniciais, vinhetas, cabeções e florões decorativos, tudo aberto em chapa de madeira. Os frontispícios das crônicas são impressos em linhas alternadas, em preto e vermelho, e ornados de escudos das armas de Portugal”, conforme esclarece o Catálogo da livraria do Conde Ameal.

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In the first part of this thesis (Chapters I and II), the synthesis, characterization, reactivity and photophysics of per(difluoroborated) tetrakis(pyrophosphito)diplatinate(II) (Pt(POPBF2)) are discussed. Pt(POP-BF2) was obtained by reaction of [Pt2(POP)4]4- with neat boron trifluoride diethyl etherate (BF3·Et2O). While Pt(POP-BF2) and [Pt2(POP)4]4- have similar structures and absorption spectra, they differ in significant ways. Firstly, as discussed in Chapter I, the former is less susceptible to oxidation, as evidenced by the reversibility of its oxidation by I2. Secondly, while the first excited triplet states (T1) of both Pt(POP-BF2) and [Pt2(POP)4]4- exhibit long lifetimes (ca. 0.01 ms at room temperature) and substantial zero-field splitting (40 cm-1), Pt(POP-BF2) also has a remarkably long-lived (1.6 ns at room temperature) singlet excited state (S1), indicating slow intersystem crossing (ISC). Fluorescence lifetime and quantum yield (QY) of Pt(POP-BF2) were measured over a range of temperatures, providing insight into the slow ISC process. The remarkable spectroscopic and photophysical properties of Pt(POP-BF2), both in solution and as a microcrystalline powder, form the theme of Chapter II.

In the second part of the thesis (Chapters III and IV), the electrochemical reduction of CO2 to CO by [(L)Mn(CO)3]- catalysts is investigated using density functional theory (DFT). As discussed in Chapter III, the turnover frequency (TOF)-limiting step is the dehydroxylation of [(bpy)Mn(CO)3(CO2H)]0/- (bpy = bipyridine) by trifluoroethanol (TFEH) to form [(bpy)Mn(CO)4]+/0. Because the dehydroxylation of [(bpy)Mn(CO)3(CO2H)]- is faster, maximum TOF (TOFmax) is achieved at potentials sufficient to completely reduce [(bpy)Mn(CO)3(CO2H)]0 to [(bpy)Mn(CO)3(CO2H)]-. Substitution of bipyridine with bipyrimidine reduces the overpotential needed, but at the expense of TOFmax. In Chapter IV, the decoration of the bipyrimidine ligand with a pendant alcohol is discussed as a strategy to increase CO2 reduction activity. Our calculations predict that the pendant alcohol acts in concert with an external TFEH molecule, the latter acidifying the former, resulting in a ~ 80,000-fold improvement in the rate of TOF-limiting dehydroxylation of [(L)Mn(CO)3(CO2H)]-.

An interesting strategy for the co-upgrading of light olefins and alkanes into heavier alkanes is the subject of Appendix B. The proposed scheme involves dimerization of the light olefin, operating in tandem with transfer hydrogenation between the olefin dimer and the light alkane. The work presented therein involved a Ta olefin dimerization catalyst and a silica-supported Ir transfer hydrogenation catalyst. Olefin dimer was formed under reaction conditions; however, this did not undergo transfer hydrogenation with the light alkane. A significant challenge is that the Ta catalyst selectively produces highly branched dimers, which are unable to undergo transfer hydrogenation.

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[ES]El Módulo de Practicum se organiza en dos materias: Prácticas escolares (38 créditos ECTS), y Trabajo fin de grado (12 créditos ECTS). Las prácticas escolares se realizarán en los dos ciclos de Educación Infantil (0-3, 3-6) y en los tres de Primaria (1ª-2º, 3º-4º, 5º-6º). Al tratarse de un Practicum progresivo, los estudiantes de los grados de Magisterio cursan la materia a lo largo del segundo, tercer y cuarto curso (Practicum I, Practicum II y Practicum III) con contenidos que tienen continuidad y que suponen un nivel de competencia superior respecto el anterior. El Practicum supone para el alumnado una oportunidad de adquirir e integrar las habilidades, los conocimientos, las competencias y la práctica necesarios para el ejercicio de su profesión, así como una ocasión para reflexionar de forma individual y grupal acerca del aprendizaje realizado. El Practicum I pretende que el alumnado establezca un primer contacto como futuros profesionales con un centro escolar, y realice una observación de carácter global, integrando los conocimientos aprendidos en la Escuela de Magisterio, ajustándolos a la diversidad del aula, a la escuela y al entorno social de ésta, y dedicando una especial atención al tratamiento de género. El Practicum II, al que se refiere esta guía, corresponde al tercer curso y se centra en el desarrollo docente de experiencias de enseñanza y aprendizaje con alumnado de la etapa, la implicación en la vida del ciclo y etapa y el ejercicio de la autocrítica y la reflexión en relación al propio desarrollo formativo y profesional. Se pretende que los estudiantes reflexionen de forma crítica sobre su conocimiento práctico inicial puesto en acción en esos contextos y sobre las condiciones que determinan su forma de pensar y actuar. El Practicum III está relacionado con las menciones (minor) y con la participación en proyectos de innovación.

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I. Sarrera. II. Azterketen enuntziatuak. III. Azterketen erantzunak: - Espazio bektorialak. - Aplikazio linealak. - Diagonalizazioa.

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De acordo com a Organização Mundial da Saúde, o período da adolescência é aquele compreendido entre os 10 e os 19 anos de idade, a população de adolescentes é crescente e um em cada cinco indivíduos encontra-se nessa faixa etária. Anualmente, 60 em cada mil jovens se tornam mães, o que faz da gravidez na adolescência tema de interesse por parte de pesquisadores de todo o mundo. No município do Rio de Janeiro, observou-se o acompanhamento da tendência nacional de aumento de gravidez precoce, com maior variação positiva encontrada na faixa etária de 10 a 14 anos. O objetivo no Artigo I: Determinar a prevalência de transtornos mentais comuns (TMC) em uma população de adolescentes grávidas e avaliar sua associação com características da gravidez e fatores socioeconômicos, demográficos e de rede social de apoio. Artigo II: Determinar a prevalência de desejo de engravidar em uma população de gestantes adolescente, verificar possíveis associações com fatores socioeconômicos, demográficos e de rede social de apoio e avaliar o papel da idade como modificador de efeito dessas associações. Foram utilizados nos Artigos I e II o método de estudo seccional de base ambulatorial realizado com 232 adolescentes grávidas, em qualquer trimestre gestacional, regularmente atendidas nos serviços de pré-natal de dois hospitais públicos especializados do município do Rio de Janeiro, de maio a outubro de 2007. Foi utilizado questionário autopreenchível para a avaliação das características da gravidez, rede social de apoio, idade, renda, escolaridade, abandono escolar, situação conjugal, raça/cor e trabalho. As análises dos TMC foram conduzidas através do GHQ-12. Os resultados no Artigo I foram, a prevalência de TMC foi de 45,3%. O modelo final ajustado mostrou associação com TMC para as seguintes variáveis: renda familiar menor que três salários mínimos (RP = 2,32; IC 95% 1,15 - 4,67), não ter apoio familiar (RP = 2,18; IC 95% 1,69-2,81), não ter amigas para conversar (RP = 1,48; IC 95% 1,13-1,92) e não ter religião (RP = 1,72; IC 95% 1,25 - 2,36). No Artigo II, foram a prevalência de desejo de engravidar entre as gestantes adolescentes foi de 46,2%. No modelo final ajustado, as variáveis que apresentaram razões de prevalência (RP) estatisticamente significantes para associação com desejo de engravidar foram: ser casada ou viver em união estável (RP = 1,80; IC 95% 1,27-2,56), não ter amigas ou amigos com quem conversar (RP = 1,48; IC 95% 1,15-1,90). Adolescentes entre 12 e 16 anos e cursando o primeiro grau desejavam menos a gravidez (RP = 0,57; IC 95% 0,38- 0,88). Artigo I: Os resultados encontrados mostram que, frente à forte associação entre TMC e gravidez em adolescentes, temos a necessidade de implementação de políticas públicas que busquem minimizar os danos decorrentes das gestações em adolescentes, através da promoção de programas que incentivem a participação familiar no processo de aceitação da gravidez, bem como propiciando espaços para discussão, onde essas jovens possam ser ouvidas e orientadas. Artigo II: Os resultados deste estudo comprovam que a gravidez na adolescência não é necessariamente indesejada. Assim, fatores como viver em união estável e não ter amigas(os) para conversar aumentam o desejo de engravidar. Por outro lado, ter entre 12 e 16 anos e ainda estar no primeiro grau diminui este desejo. Tais achados podem ajudar os profissionais de saúde que lidam com essa faixa etária a identificar possíveis situações de risco para a gravidez e assim direcionar sua orientação de forma precisa e adequada.

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Esta investigação tem como tema a proposta de formação de professores em serviço do Curso de Atualização de Professores de Escola de Horário Integral, realizado no segundo governo de Leonel Brizola, no Estado do Rio de Janeiro (1991 1994), durante o Segundo Programa Especial de Educação (II PEE). Este estudo objetivou analisar a proposta de formação de professores em serviço, focalizando este Curso como uma das iniciativas desta formação e, partindo dela identificar contribuições significativas, produzidas naquele tempo e espaço específico, que possam enriquecer e suscitar questões para os debates atuais sobre a formação continuada de professores. Ao empreender esta tarefa se julgou necessário delinear a trajetória do I E II PEE para melhor compreensão da evolução deste plano e de sua proposta de formação de professores, até a elaboração do Curso. Após a retomada do II PEE, frente à necessidade de reestruturação pedagógica dos Centros Integrados de Educação Pública (CIEPs) foi criado o Curso, em convênio com a UERJ. O ponto mais importante identificado nesta proposta de formação foi considerar a escola como lócus de formação continuada tendo como base o saber do professor neste processo. Aspecto como se pode constatar, de grande relevância atualmente nas discussões sobre a temática, mas que naquele momento foi uma inovação. Supõe-se que os resultados deste trabalho poderão contribuir para ampliar os debates em torno das questões voltadas para a formação continuada de professores, e ainda, ampliar os debates, bem oportunos, sobre criação de diferentes alternativas de escolas públicas de horário integral, com suas proposta de formação para atender a uma necessidade da sociedade contemporânea e fundamentar ações de gestores das políticas públicas de Educação.

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通过实验我们证明Ca2+对叶绿体膜的流动性,对PS I和PS II叶绿素蛋白质复合物的相对含量,以及PS I和PS II的多肽均有影响。 Ca2+对叶绿体膜表层的流动性影响不大,但降低了叶绿体膜深层脂质分子的流动性。从另一个角度阐明了Ca2+抑制光能从PS II向PS I传递的机制。 Ca2+可使PS I的21,23,110KD的多肽转移至PS II,LHCP1和LHCP2中的CF1的两个亚基(55,60KD)转至CPa和LHCP3,从而增加了PS II的捕光截面,引起激发能在两个系统之间的分配的改变。 用免疫学方法可以证明CPIa2和LHCP2的Ab为复合抗体,CPIa1的Ab为单抗,我们可以推测向日葵的不同叶绿素蛋白质复合物具有同源性。

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Phyrobilisomes (PBS) are the major light-harvesting, protein-pigment complexes in cyanobacteria and red algae. PBS absorb and transfer light energy to photosystem (PS) II as well as PS I, and the distribution of light energy from PBS to the two photosystems is regulated by light conditions through a mechanism known as state transitions. In this study the quantum efficiency of excitation energy transfer from PBS to PS I in the cyanobacterium Synechococcus sp. PCC 7002 was determined, and the results showed that energy transfer from PBS to PS I is extremely efficient. The results further demonstrated that energy transfer from PBS to PS I occurred directly and that efficient energy transfer was dependent upon the allophycocyanin-B alpha subunit, ApcD. In the absence of ApcD, cells were unable to perform state transitions and were trapped in state 1. Action spectra showed that light energy transfer from PBS to PS I was severely impaired in the absence of ApcD. An apcD mutant grew more slowly than the wild type in light preferentially absorbed by phyrobiliproteins and was more sensitive to high light intensity. On the other hand, a mutant lacking ApcF, which is required for efficient energy transfer from PBS to PS II, showed greater resistance to high light treatment. Therefore, state transitions in cyanobacteria have two roles: (1) they regulate light energy distribution between the two photosystems; and (2) they help to protect cells from the effects of light energy excess at high light intensities. (C) 2009 Elsevier B.V. All rights reserved.

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Structures and crystal form transition of the novel aryl ether ketone polymer containing meta-phenylene linkage: PEKEKK(T/I) were investigated by wide angle X-ray diffraction (WAXD), imaging plates (IPs) and small angle X-ray scattering (SAXS). The energy of activation of the decomposition reaction and degree of crystallinity of PEKEKK(T/I) were determined by WAXD and thermo-gravimetric analysis (TGA), respectively. Results obtained from WAXD and IPs show that crystal forms I and II coexist in the PEKEKK(T/I) samples isothermally cold crystallized in the temperature range from 180degreesC to 240degreesC and only form I occurs in PEKEKK(T/I) samples isothermally cold crystallized at 270degreesC. The radius of gyration (Rg), thickness of microregions with electron-density fluctuations (E) and distribution of particle sizes were investigated by SAXS.

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Epitaxial crystallization of syndiotactic polypropylene (sPP) on 2-quinoxalinol (2-Quin) yields, in the lower part of the crystallization range, the less common and metastable form II based on the packing of isochiral helices, rather than the stable antichiral form I. The contact plane is (110)(II). Form II exits only as a thin layer (< 50 nm) near the substrate surface. During further growth away from the surface, a transition takes place to the disordered form I, observed in "conventional" thin film growth. The epitaxial relationship rests only partly on dimensional matching with the chain axis repeat distance (which would be valid for both forms I and II) and on interchain distances. Whereas a better dimensional match would be achieved with form I, selection of the isochiral form II results from better correspondence of the surface topographies of the deposit (110)(II) sPP and substrate 2-Quin (001) contact faces.

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Investigations of the vibrational spectra of cyclo(Gly-Gly), cyclo(L-Ala-L-Ala) and cyclo(t-Ala-Gly) are reported. Raman scattering and Fourier transform infrared (FTIR) spectra of solid-state and aqueous protonated samples, as well as their corresponding N-deuterated isotopomers, have been examined. In addition, density functional theory (DFT) (B3-LYP/cc-pVDZ) calculations of molecular structures and their associated vibrational modes were carried out. In each case, the calculated structures of lowest energy for the isolated gas-phase molecules have boat conformations. Assignments have been made for the observed Raman and FTIR vibrational bands of the cyclic di-amino acid peptides (CDAPs) examined. Raman polarization studies of aqueous phase samples are consistent with C-2 and C-1 symmetries for the six-membered rings of cyclo(L-Ala-L-Ala) and cydo(L-Ala-Gly), respectively. There is a good correlation between experimental and calculated vibrational bands for the three CDAPs. These data are in keeping with boat conformations for cydo(L-Ala-L-Ala) and cyclo(L-Ala-Gly) molecules, predicted by the ab initio calculations, in both the solid and aqueous solution states. However, Raman spectroscopic results might infer that cyclo(L-AlaGly) deviates only slightly from planarity in the solid state. The potential energy distributions of the amide I and II modes of a cis-peptide linkage are shown to be significantly different from those of the trans-peptides. For example, deuterium shifts have shown that the cis-amide I vibrations found in cyclo(Gly-Gly), cyclo(L-Ala-L-Ala), and cyclo(L-Ala-Gly) have larger N-H contributions compared to their trans-amide counterparts. Compared to trans-amide II vibrations, cis-amide II vibrations show a considerable decrease in N-H character.

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Death receptors can directly (type I cells) or indirectly induce apoptosis by activating mitochondrial-regulated apoptosis (type II cells). The level of caspase 8 activation is thought to determine whether a cell is type I or II, with type II cells less efficient at activating this caspase following death receptor activation. FLICE-inhibitory protein (FLIP) blocks death receptor-mediated apoptosis by inhibiting caspase 8 activation; therefore, we assessed whether silencing FLIP could convert type II cells into type I. FLIP silencing-induced caspase 8 activation in Bax wild-type and null HCT116 colorectal cancer cells; however, complete caspase 3 processing and apoptosis were only observed in Bax wild-type cells. Bax-null cells were also more resistant to chemotherapy and tumor necrosis factor-related apoptosis inducing ligand and, unlike the Bax wild-type cells, were not sensitized to these agents by FLIP silencing. Further analyses indicated that release of second mitochondrial activator of caspases from mitochondria and subsequent inhibition of X-linked inhibitor of apoptosis protein (XIAP) was required to induce full caspase 3 processing and apoptosis following FLIP silencing. These results indicate that silencing FLIP does not necessarily bypass the requirement for mitochondrial involvement in type II cells. Furthermore, targeting FLIP and XIAP may represent a therapeutic strategy for the treatment of colorectal tumors with defects in mitochondrial-regulated apoptosis.

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Women’s contribution to abstract art in the interwar period is a subject that, to date, has received very little attention. In this article we deal with the untold story of the participation of women artists in Abstraction-Création, the foremost international group dedicated to abstract art in the 1930s. Founded in Paris in 1931, the group took on the work of two previous collectives to become a platform for the dissemination and promotion of abstract art and consisted of around a hundred members. Twelve of these were women, whose writings and works were published in the group’s annual magazine, abstraction creátion art non figuratif (1932-1936), and who participated in a number of the group’s exhibitions. Compared to what had occurred in previous groups, the participation of women, although reduced in number, was comparable to that of the male artists and being members of the group had a generally positive impact on the women’s careers. However, all this came at the expense of relinquishing any gender specificity in their work and the public presentation of it, and demonstrates that the normalization of women’s contributions to the avant-garde could only be brought about alongside a questioning of the more dogmatic views of modernity.

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For the purposes of identifying microlensing events, the POINT-AGAPE collaboration has been monitoring the Andromeda galaxy (M31) for three seasons (1999-2001) with the Wide Field Camera on the Isaac Newton Telescope. In each season, data are taken for one hour per night for roughly 60 nights during the six months that M31 is visible. The two 33 x 33 arcmin(2) fields of view straddle the central bulge, northwards and southwards. We have calculated the locations, periods and brightness of 35 414 variable stars in M31 as a by-product of the microlensing search. The variables are classified according to their period and brightness. Rough correspondences with classical types of variable star (such as Population I and II Cepheids, Miras and semiregular long-period variables) are established. The spatial distribution of Population I Cepheids is clearly associated with the spiral arms, while the central concentration of the Miras and long-period variables varies noticeably, the brighter and the shorter period Miras being much more centrally concentrated.